Calcgrid

Use this when you need a deterministic Poland working-day offset. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when nationwide statutory holiday list only. Saturday substitute dates, individual work schedules, employer, sector, school, bank and local schedules are not inferred. What it computes: Adds or subtracts Poland authority-scope working days in exact coverage. Example user requests: Add or subtract Poland working days around Christmas Eve. | Add or subtract Poland working days around Ordinary weekday. Inputs: start_date (date); working_days (integer). Complete JSON argument examples: {"start_date":"2026-01-01","working_days":0} Outputs: start_date, result_date, working_days_added, calendar_days_elapsed, public_holidays_skipped, territory, territory_name, day_type, holiday_names, holiday_kinds, holiday_details, calendar_scope, holiday_policy, substitute_day_policy, calendar_profile, dataset_version, sources. Formula: move one day at a time; decrement only on status.is_working_day=true Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/poland-public-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/poland-public-add-working-days.md

Use this when you need a deterministic Portugal working-day offset. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when mandatory nationwide list only. Municipal, autonomous-region, collective-agreement, employer and locally substituted holiday schedules are not inferred. What it computes: Adds or subtracts Portugal authority-scope working days in exact coverage. Example user requests: Add or subtract Portugal working days around Portugal Day. | Add or subtract Portugal working days around Ordinary weekday. Inputs: start_date (date); working_days (integer). Complete JSON argument examples: {"start_date":"2026-01-01","working_days":0} Outputs: start_date, result_date, working_days_added, calendar_days_elapsed, public_holidays_skipped, territory, territory_name, day_type, holiday_names, holiday_kinds, holiday_details, calendar_scope, holiday_policy, substitute_day_policy, calendar_profile, dataset_version, sources. Formula: move one day at a time; decrement only on status.is_working_day=true Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/portugal-public-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/portugal-public-add-working-days.md

Use this when you need a deterministic Romania working-day offset. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when romania 2026 statutory holiday layer only, with required calendar_basis and work_schedule=mon_fri_planning. The basis selects dates, not a person's identity or religion. No union of Christian calendars, non-Christian additional holidays, public-sector bridge/recovery days, individual rosters, shift exceptions, bank/exchange/school opening, payroll or legal deadlines are computed. Other bases and future years are unsupported. What it computes: Adds or subtracts Romania authority-scope working days in exact coverage. Explicit calendar_basis and mon_fri_planning required; no union of calendars or personal roster inference. Example user requests: Add or subtract Romania working days around January 24 remains a statutory holiday even on Saturday. | Add or subtract Romania working days around Selected-calendar Good Friday. Inputs: start_date (date); working_days (integer); calendar_basis (enum); work_schedule (enum). Complete JSON argument examples: {"start_date":"2026-01-01","working_days":0,"calendar_basis":"romanian_orthodox","work_schedule":"mon_fri_planning"} | {"start_date":"2026-01-01","working_days":0,"calendar_basis":"roman_catholic","work_schedule":"mon_fri_planning"} Outputs: start_date, result_date, working_days_added, calendar_days_elapsed, public_holidays_skipped, territory, territory_name, day_type, holiday_names, holiday_kinds, holiday_details, calendar_scope, holiday_policy, substitute_day_policy, calendar_profile, dataset_version, sources, calendar_basis, work_schedule, is_statutory_holiday, payroll_scope, personal_roster_scope, additional_religious_holidays_scope. Formula: planning_workday = weekday AND no statutory holiday in the explicitly selected calendar_basis Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/romania-public-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/romania-public-add-working-days.md

Use this when you need a deterministic Russia working-day offset. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when this package covers the federal statutory/public-holiday layer and the Government-published 2026 transfer days over a Saturday-Sunday baseline. Regional holidays, republic/local holidays, employer, bank, school, shift, sector and collective-agreement schedules are not inferred. Future annual transfer resolutions require a refreshed package. What it computes: Adds or subtracts Russia authority-scope working days in exact coverage. Example user requests: Add or subtract Russia working days around Russia New Year's holiday. | Add or subtract Russia working days around Published transfer day. | Add or subtract Russia working days around Ordinary Russia working day. Inputs: start_date (date); working_days (integer). Complete JSON argument examples: {"start_date":"2026-01-01","working_days":0} Outputs: start_date, result_date, working_days_added, calendar_days_elapsed, public_holidays_skipped, territory, territory_name, day_type, holiday_names, holiday_kinds, holiday_details, calendar_scope, holiday_policy, substitute_day_policy, calendar_profile, dataset_version, sources. Formula: move one day at a time; decrement only on status.is_working_day=true Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/russia-public-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/russia-public-add-working-days.md

Use this when you need a deterministic Saudi Arabia working-day offset. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when financial-institution scope only. MHRSD business-sector leave, RTGS-specific intervals, government offices, private-employer rosters, Hajj-season branch exceptions and Umm al-Qura forecasts are not inferred. What it computes: Adds or subtracts Saudi Arabia authority-scope working days in exact coverage. Example user requests: Add or subtract Saudi Arabia working days around SAMA Eid Al-Fitr interval. | Add or subtract Saudi Arabia working days around Friday/Saturday weekly baseline. | Add or subtract Saudi Arabia working days around National Day Saturday substitution. Inputs: start_date (date); working_days (integer). Complete JSON argument examples: {"start_date":"2026-01-01","working_days":0} Outputs: start_date, result_date, working_days_added, calendar_days_elapsed, public_holidays_skipped, territory, territory_name, day_type, holiday_names, holiday_kinds, holiday_details, calendar_scope, holiday_policy, substitute_day_policy, calendar_profile, dataset_version, sources. Formula: move one day at a time; decrement only on status.is_working_day=true Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/saudi-financial-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/saudi-financial-add-working-days.md

Use this when you need a deterministic Sweden working-day offset. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when nationwide statutory list only. Midsummer Eve, Christmas Eve, New Year's Eve, employer, collective-agreement, sector, school, bank and local closures are not inferred; Sunday is already excluded by the weekday baseline. What it computes: Adds or subtracts Sweden authority-scope working days in exact coverage. Example user requests: Add or subtract Sweden working days around National Day. | Add or subtract Sweden working days around Midsummer Eve is not statutory. Inputs: start_date (date); working_days (integer). Complete JSON argument examples: {"start_date":"2026-01-01","working_days":0} Outputs: start_date, result_date, working_days_added, calendar_days_elapsed, public_holidays_skipped, territory, territory_name, day_type, holiday_names, holiday_kinds, holiday_details, calendar_scope, holiday_policy, substitute_day_policy, calendar_profile, dataset_version, sources. Formula: move one day at a time; decrement only on status.is_working_day=true Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/sweden-public-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/sweden-public-add-working-days.md

Use this when you need a deterministic Slovenia working-day offset. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when slovenia 2026 statutory work-free dates over an explicitly selected Monday-Friday planning baseline. Seven named state holidays are not work-free; no extra Monday or bridge day is invented. Individual shifts, replacement weekly rest, employer/local/sector/school/bank schedules, religious leave, payroll, legal deadlines and future years are not computed. What it computes: Adds or subtracts Slovenia authority-scope working days in exact coverage. Requires explicit mon_fri_planning; seven named state holidays do not add rest. Example user requests: Add or subtract Slovenia working days around Easter Monday is statutory rest. | Add or subtract Slovenia working days around Whit Monday is not Whit Sunday. | Add or subtract Slovenia working days around Science Day is a state holiday without rest. Inputs: start_date (date); working_days (integer); work_schedule (enum). Complete JSON argument examples: {"start_date":"2026-01-01","working_days":0,"work_schedule":"mon_fri_planning"} Outputs: start_date, result_date, working_days_added, calendar_days_elapsed, public_holidays_skipped, territory, territory_name, day_type, holiday_names, holiday_kinds, holiday_details, calendar_scope, holiday_policy, substitute_day_policy, calendar_profile, dataset_version, sources, work_schedule, is_state_holiday, is_statutory_non_working_day, is_non_rest_state_holiday, personal_roster_scope, payroll_scope. Formula: planning_workday = weekday AND no statutory_work_free_event Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/slovenia-public-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/slovenia-public-add-working-days.md

Use this when you need a deterministic Singapore date offset in 2026-2027 and accept the stated employer-rest-day limitation. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need an employer-specific roster, bank/exchange calendar or a date outside 2026-2027. What it computes: Adds or subtracts dates using Singapore's pinned national public-holiday dates and the CLDR Saturday/Sunday baseline. Example user requests: Add five Singapore working days after 2027-02-05. Inputs: start_date (date); working_days (integer). Complete JSON argument examples: {"start_date":"2027-02-05","working_days":5} Outputs: start_date, result_date, working_days_added, calendar_days_elapsed, public_holidays_skipped, territory, territory_name, day_type, holiday_names, holiday_observed, weekend_days, rest_day_policy, calendar_scope, calendar_profile, source_quality, dataset_version, sources. Formula: move one day at a time; decrement remaining only when Singapore status.is_working_day=true Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/singapore-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/singapore-add-working-days.md

Use this when you need a deterministic Slovakia working-day offset. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when pinned Slovakia 2026 statutory rest-day layer over an explicitly declared Monday-Friday planning baseline, not an individual roster. The holidays on May 8 and September 15 are not statutory rest days in 2026; September 1, October 28 and November 17 are state holidays without rest under section 2(3). Do not infer substitute Mondays, payroll premiums, leave rights, retail closures, shift, bank, school, employer or future-year schedules. Later legal changes require a new snapshot. What it computes: Adds or subtracts Slovakia authority-scope working days in exact coverage. Distinguishes 11 rest-day holidays from five named holidays without statutory rest in 2026. Example user requests: Add or subtract Slovakia working days around May 8 is a named holiday but a working date. | Add or subtract Slovakia working days around Good Friday. | Add or subtract Slovakia working days around November 17 is not statutory rest. Inputs: start_date (date); working_days (integer). Complete JSON argument examples: {"start_date":"2026-01-01","working_days":0} Outputs: start_date, result_date, working_days_added, calendar_days_elapsed, public_holidays_skipped, territory, territory_name, day_type, holiday_names, holiday_kinds, holiday_details, calendar_scope, holiday_policy, substitute_day_policy, calendar_profile, dataset_version, sources, holiday_rest_status, payroll_scope. Formula: working = weekday outside the declared weekly rest and outside statutory_rest_holiday dates Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/slovakia-public-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/slovakia-public-add-working-days.md

Use this when you need a deterministic South Africa national public-holiday offset. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need an employer-specific exchanged holiday or non-national schedule. What it computes: Adds or subtracts South Africa national working days in exact 2026-2027 coverage. Example user requests: Add one South Africa working day after 2026-11-03. Inputs: start_date (date); working_days (integer). Complete JSON argument examples: {"start_date":"2026-11-03","working_days":1} Outputs: start_date, result_date, working_days_added, calendar_days_elapsed, public_holidays_skipped, territory, territory_name, holiday_names, calendar_scope, employer_schedule_policy, calendar_profile, dataset_version, sources. Formula: move one day at a time; decrement only on South Africa status.is_working_day=true Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/south-africa-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/south-africa-add-working-days.md

Use this when you need a deterministic Thailand working-day offset. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when this is a Bank of Thailand financial-institution calendar, not a universal Thai employee, government, employer, exchange or payment-settlement calendar. Bangkok-only, Islamic-bank and southern-branch conditions remain explicit and are not generalized. What it computes: Adds or subtracts Thailand authority-scope working days in exact coverage. Example user requests: Add or subtract Thailand working days around 2027 substitution. | Add or subtract Thailand working days around Bangkok-only event remains conditional. Inputs: start_date (date); working_days (integer). Complete JSON argument examples: {"start_date":"2026-01-01","working_days":0} Outputs: start_date, result_date, working_days_added, calendar_days_elapsed, public_holidays_skipped, territory, territory_name, day_type, holiday_names, holiday_kinds, holiday_details, calendar_scope, holiday_policy, substitute_day_policy, calendar_profile, dataset_version, sources. Formula: move one day at a time; decrement only on status.is_working_day=true Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/thailand-financial-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/thailand-financial-add-working-days.md

Use this when you need a deterministic Türkiye statutory working-day offset in 2026-2027. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need an employer or sector calendar, or the date falls outside the pinned coverage. What it computes: Adds or subtracts dates using Türkiye's pinned statutory public-holiday package; published half-days are skipped conservatively. Example user requests: Add one Türkiye statutory working day after 2027-03-05. Inputs: start_date (date); working_days (integer). Complete JSON argument examples: {"start_date":"2027-03-05","working_days":1} Outputs: start_date, result_date, working_days_added, calendar_days_elapsed, holidays_skipped, territory, territory_name, day_type, holiday_names, holiday_kinds, half_day_start_time, non_working_fraction, weekend_days, calendar_scope, half_day_policy, rest_day_policy, calendar_profile, dataset_version, sources. Formula: move one day at a time; decrement only when status.is_working_day=true Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/turkey-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/turkey-add-working-days.md

Use this when you need a deterministic 中国台湾省 working-day offset. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when government administrative-agency scope only. Public enterprises generally follow the calendar, but special agencies, schools, private employers, local arrangements, banks, exchanges and sector schedules are not inferred. What it computes: Adds or subtracts 中国台湾省 authority-scope working days in exact coverage. Example user requests: Add or subtract 中国台湾省 working days around Spring Festival substitute holiday. | Add or subtract 中国台湾省 working days around Government calendar does not mean private-employer closure. Inputs: start_date (date); working_days (integer). Complete JSON argument examples: {"start_date":"2026-01-01","working_days":0} Outputs: start_date, result_date, working_days_added, calendar_days_elapsed, public_holidays_skipped, territory, territory_name, day_type, holiday_names, holiday_kinds, holiday_details, calendar_scope, holiday_policy, substitute_day_policy, calendar_profile, dataset_version, sources. Formula: move one day at a time; decrement only on status.is_working_day=true Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/taiwan-government-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/taiwan-government-add-working-days.md

Use this when you need a deterministic UAE federal-government offset inside 2026. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need a private employer, local-government or future-year calendar. What it computes: Adds or subtracts dates using the exact 2026 UAE federal-government holiday package and Monday-Friday baseline. Example user requests: Add five UAE federal-government working days after 2026-08-27. Inputs: start_date (date); working_days (integer). Complete JSON argument examples: {"start_date":"2026-08-27","working_days":1} Outputs: start_date, result_date, working_days_added, calendar_days_elapsed, public_holidays_skipped, territory, territory_name, jurisdiction, day_type, weekend_days, holiday_names, holiday_legal_bases, calendar_scope, private_sector_policy, unresolved_lunar_rules, calendar_profile, dataset_version, sources. Formula: move one day at a time; decrement remaining only when UAE federal status.is_working_day=true Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/uae-federal-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/uae-federal-add-working-days.md

Use this when you need a deadline a stated number of UK working days before or after a 2024-2028 date and the correct division's bank holidays matter. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need calendar days, a local/employer/market calendar, a non-UK jurisdiction or a result outside 2024-2028. What it computes: Adds or subtracts working days for England and Wales, Scotland or Northern Ireland, skipping weekends and the selected division's official bank holidays. Example user requests: What date is five England and Wales working days after 23 December 2026? | Add two Scottish working days to 12 June 2026, accounting for the official bank holiday. | Subtract ten Northern Ireland business days from 20 July 2027. Inputs: start_date (date); working_days (integer, working days); division (enum, optional). Complete JSON argument examples: {"start_date":"2026-12-23","working_days":5,"division":"england-and-wales"} | {"start_date":"2026-06-12","working_days":2,"division":"scotland"} Outputs: division, division_name, start_date, result_date, result_weekday, result_is_working_day, working_days_added [working days], calendar_days_elapsed [days], non_working_days_skipped [days], bank_holidays_skipped, dataset_version, coverage_start, coverage_end, source_snapshot_sha256. Formula: move one calendar day at a time in sign(working_days); decrement only when the selected UK division reports is_working_day=true Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/uk-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/uk-add-working-days.md

Use this when you need a deterministic US federal employee/office date offset in 2026-2027. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need state/local/private-employer, exchange or alternate-work-schedule semantics. What it computes: Adds or subtracts dates using the pinned OPM federal schedule and US weekend baseline. Example user requests: Add five US federal working days after 2027-06-17. Inputs: start_date (date); working_days (integer). Complete JSON argument examples: {"start_date":"2027-06-17","working_days":1} Outputs: start_date, result_date, working_days_added, calendar_days_elapsed, federal_holidays_skipped, territory, territory_name, day_type, holiday_names, holiday_observed, holiday_actual_dates, weekend_days, rest_day_policy, calendar_scope, calendar_profile, source_quality, dataset_version, sources. Formula: move one day at a time; decrement remaining only when US federal status.is_working_day=true Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/us-federal-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/us-federal-add-working-days.md

Use this when you need a deterministic workday offset and know the workweek variant. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the workweek or employer/shift scope is unknown. What it computes: Adds or subtracts Uzbekistan 2026 workdays under a required five-day or six-day schedule. Example user requests: Add five five-day-workweek working days after 2026-12-28. Inputs: start_date (date); workweek (integer); working_days (integer). Complete JSON argument examples: {"start_date":"2026-12-28","workweek":5,"working_days":1} Outputs: start_date, result_date, working_days_added, calendar_days_elapsed, public_holidays_skipped, territory, territory_name, workweek, weekly_rest_model, weekday, is_working_day, day_type, weekend_days, holiday_names, holiday_kinds, holiday_details, calendar_scope, substitute_day_policy, calendar_profile, dataset_version, sources. Formula: move one day at a time; decrement only when selected status is working Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/uzbekistan-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/uzbekistan-add-working-days.md

Use this when you need a deterministic Vietnam working-day offset. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when public-sector and statutory paid-holiday layer only; private-employer, non-Saturday/Sunday workweeks, provincial, sector, bank, school and employer schedules are not inferred. The proposed four-day 2026 Vietnam Cultural Day public-sector arrangement is not encoded until finally approved. What it computes: Adds or subtracts Vietnam authority-scope working days in exact coverage. Example user requests: Add or subtract Vietnam working days around New Year transfer. | Add or subtract Vietnam working days around Vietnam Cultural Day. Inputs: start_date (date); working_days (integer). Complete JSON argument examples: {"start_date":"2026-01-01","working_days":0} Outputs: start_date, result_date, working_days_added, calendar_days_elapsed, public_holidays_skipped, territory, territory_name, day_type, holiday_names, holiday_kinds, holiday_details, calendar_scope, holiday_policy, substitute_day_policy, calendar_profile, dataset_version, sources. Formula: move one day at a time; decrement only on status.is_working_day=true Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/vietnam-public-add-working-days with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/vietnam-public-add-working-days.md

Use this when you have visitors and conversions for a control and a variant (A/B test, split test, email test) and need to know whether the difference is statistically significant. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the metric is a mean (revenue per user, time on page) rather than a conversion proportion, or there are more than two variants (use a chi-square or multiple-comparison procedure). What it computes: Tests whether a variant's conversion rate differs from the control's using the pooled two-proportion z-test, and reports both rates, absolute and relative lift, z-score, two-sided p-value, a confidence interval for the difference and the sample size needed per variant to detect the observed lift with 80 % power. Inputs: control_visitors (integer); control_conversions (integer); variant_visitors (integer); variant_conversions (integer); confidence_level_percent (number, %, optional). Complete JSON argument examples: {"control_visitors":1000,"control_conversions":50,"variant_visitors":1000,"variant_conversions":70} | {"control_visitors":5000,"control_conversions":200,"variant_visitors":5000,"variant_conversions":260} Outputs: control_rate_percent [%], variant_rate_percent [%], absolute_lift_percentage_points [pp], relative_lift_percent [%], standard_error_percentage_points [pp], z_score, p_value, significant, ci_lower_percentage_points [pp], ci_upper_percentage_points [pp], required_visitors_per_variant, verdict. Formula: p1 = x1/n1, p2 = x2/n2, p̄ = (x1 + x2)/(n1 + n2); z = (p2 − p1) / √(p̄(1 − p̄)(1/n1 + 1/n2)); p_value = 2·(1 − Φ(|z|)); CI = (p2 − p1) ± z_crit·√(p1(1 − p1)/n1 + p2(1 − p2)/n2); n per variant = (z_crit·√(2·p̄(1 − p̄)) + z_0.80·√(p1(1 − p1) + p2(1 − p2)))² / (p2 − p1)² Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/ab-test-significance with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/business/ab-test-significance.md

Use this when you need someone's exact age on a date, the total number of days lived, the weekday they were born on, or how many days remain until their next birthday. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need the difference between two arbitrary dates with a business-day count (use date-difference) or a countdown to an event (use days-until). What it computes: Computes the exact age on a given date as years, months and days by Gregorian calendar arithmetic, plus total days and weeks, the weekday of birth, and the date of and days until the next birthday. Inputs: birth_date (date); as_of_date (date, optional). Complete JSON argument examples: {"birth_date":"1990-05-17","as_of_date":"2026-09-23"} | {"birth_date":"1985-12-25","as_of_date":"2026-01-10"} Outputs: years, months, days, age_text, total_days [days], total_weeks [weeks], age_decimal_years [years], next_birthday_date, days_until_next_birthday [days], day_of_week_born. Formula: years, months, days = calendar difference birth_date → as_of_date (when the day-of-month is smaller, days are borrowed from the month before as_of_date); total_days = as_of_date − birth_date; total_weeks = total_days / 7; age_decimal_years = total_days / 365.2425; next_birthday = first (month, day) of birth on or after as_of_date Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/age with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/age.md

Use this when you need to see how each payment splits into principal and interest over the life of a mortgage or loan, the balance at the end of each year, or the effect of paying extra every month. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you only need the payment amount (use loan-payment or mortgage-payment), or you know the payment and want the payoff time of a revolving balance (use debt-payoff). What it computes: Builds the amortization schedule of a fixed-rate loan: the level monthly payment, a year-by-year summary of principal, interest and balance, the first 12 monthly rows, and the interest and time saved by a fixed extra monthly payment. Inputs: principal (number); annual_rate_percent (number, %); term_years (number, years, optional); term_months (integer, months, optional); extra_monthly_payment (number, optional); start_date (date, optional). Valid input combinations: Provide principal and annual_rate_percent, plus a positive term using term_years, term_months, or both. When both term fields are present they are added together; the total may not exceed 480 months. Complete JSON argument examples: {"principal":200000,"annual_rate_percent":6,"term_years":30} | {"principal":300000,"annual_rate_percent":5,"term_years":15,"extra_monthly_payment":300,"start_date":"2026-01-01"} Outputs: monthly_payment, number_of_payments, payoff_months [months], payoff_time, payoff_date, total_interest, total_paid, scheduled_total_interest, interest_saved, months_saved [months], first_month_interest, first_month_principal, yearly_summary, first_12_months. Formula: i = annual_rate_percent / 1200; n = 12·term_years + term_months; monthly_payment = principal × i / (1 − (1 + i)^−n) (principal / n if i = 0). Each month: interest = balance × i; principal_paid = monthly_payment + extra_monthly_payment − interest (capped at the balance); balance −= principal_paid, until the balance is 0. Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/amortization-schedule with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/finance/amortization-schedule.md

Use this when you need the four stem-branch pillars (年柱 月柱 日柱 时柱) of a birth moment, the day master and its ten-god relations, element balance, or the start age and sequence of the 大运 luck pillars. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you only need the lunar date or zodiac of a date (use lunar-calendar-converter or chinese-zodiac), the stem-branch of a single date without an hour (use sexagenary-cycle), or an interpretation of the chart — this tool computes the traditional chart only and gives no predictions. What it computes: Builds the Bazi (八字, Bāzì) / Four Pillars (四柱) chart of a birth date and time: year pillar by 立春 (Lìchūn), month pillar by the 节 (jié) solar terms, day pillar from the sexagenary day count, hour pillar by the 五鼠遁 (Wǔshǔdùn) rule, plus day master, five-element counts, ten gods (十神), hidden stems (藏干), 纳音 (nàyīn), void branches (空亡) and the ten-year luck pillars (大运). Inputs: birth_date (date); birth_time (string); sex (enum); utc_offset_hours (number, h, optional); longitude_degrees (number, °, optional); late_zi_next_day (boolean, optional); include_hidden_stems (boolean, optional). Complete JSON argument examples: {"birth_date":"1990-05-17","birth_time":"08:30","sex":"male","utc_offset_hours":8} | {"birth_date":"2000-01-01","birth_time":"00:30","sex":"female","utc_offset_hours":8} Outputs: bazi_chart, year_pillar, month_pillar, day_pillar, hour_pillar, pillars_pinyin, pillars_english, day_master, zodiac, five_element_counts, missing_elements, dominant_element, ten_gods, hidden_stems, nayin, void_branches, luck_direction, luck_start_age, luck_start_age_years [years], luck_pillars, lunar_birth_date, solar_term_context, time_used, notes. Formula: year = solarYearAtLichun(birth instant); month stem = ((year stem mod 5) × 2 + 2 + months since 寅) mod 10; day index = (JDN + 49) mod 60; hour stem = ((day stem mod 5) × 2 + hour branch) mod 10; hour branch = floor(((hour + 1) mod 24) / 2); true solar time = clock + (longitude − 15 × utc_offset) × 4 min + equation of time; 起运 years = days to 节 / 3 Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/bazi-four-pillars with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/lunar/bazi-four-pillars.md

Use this when you need an adult's BMI, its WHO/CDC weight category, or the weight range that corresponds to a normal BMI (18.5–24.9) for a given height. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the person is under 20 years old (children need age- and sex-specific BMI percentiles), or you need body-fat percentage (use body-fat) or calorie needs (use bmr / tdee). What it computes: Computes body mass index (BMI) from weight and height and classifies it with the WHO adult categories, plus the healthy weight range for that height. Inputs: weight_kg (number, kg); height_cm (number, cm). Complete JSON argument examples: {"weight_kg":70,"height_cm":175} | {"weight_kg":95,"height_cm":180} Outputs: bmi [kg/m²], category, healthy_weight_min_kg [kg], healthy_weight_max_kg [kg], prime. Formula: BMI = weight_kg / (height_cm / 100)² Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/bmi with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/health/bmi.md

Use this when you need resting daily calorie needs for an adult from sex, weight, height and age, as a base for diet or TDEE calculations. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need total daily calories including activity (use tdee), the person is a child, pregnant, or has very high muscle mass (use a body-fat based equation such as Katch-McArdle instead). What it computes: Estimates basal metabolic rate (calories burned at complete rest per day) with the Mifflin-St Jeor equation, and also reports the revised Harris-Benedict estimate. Inputs: sex (enum); weight_kg (number, kg); height_cm (number, cm); age_years (number, years). Complete JSON argument examples: {"sex":"male","weight_kg":70,"height_cm":175,"age_years":30} | {"sex":"female","weight_kg":60,"height_cm":165,"age_years":40} Outputs: bmr_kcal_per_day [kcal/day], harris_benedict_kcal_per_day [kcal/day], bmr_kj_per_day [kJ/day]. Formula: Mifflin-St Jeor: BMR = 10·weight_kg + 6.25·height_cm − 5·age_years + 5 (male) or − 161 (female). Harris-Benedict (1984): male 88.362 + 13.397·W + 4.799·H − 5.677·A; female 447.593 + 9.247·W + 3.098·H − 4.330·A. Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/bmr with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/health/bmr.md

Use this when you need an SLA, support, procurement or order deadline measured in business hours under the published mainland China or UK calendar, and must express the result in another team's IANA time zone with reproducible holiday and DST evidence. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need calendar hours, an overnight or split shift, lunch breaks, an employer/local/market calendar, a legal filing deadline, actual delivery/arrival prediction, private calendar availability, or a date outside the selected evidence package's coverage. What it computes: Adds an explicit number of business hours inside a caller-supplied daily window, using either the official mainland China work calendar or a selected GOV.UK division, then returns the deadline in UTC, the calendar zone and a target IANA zone with a complete segment/skip audit trail. Example user requests: A Shanghai support ticket opened at 2026-09-24 15:00 has a 16-business-hour SLA, counted from that day during 09:00-17:00 China official working time. When is it due in London? | Starting 24 December 2026 at 15:00 London time, add 8 England-and-Wales business hours between 09:00 and 17:00 and show the deadline in Shanghai. | 按中国官方工作日，从 2026-09-24 15:00（上海）起计算 16 个营业小时，每天 09:00-17:00，起始日计入；给出伦敦时间和跳过日期。 Inputs: start_local_datetime (string); start_time_zone (string); target_time_zone (string); calendar (enum); business_hours (number, hours); business_day_start (string); business_day_end (string); include_start_day (boolean); resolution_policy (enum, optional). Complete JSON argument examples: {"start_local_datetime":"2026-09-24T15:00:00","start_time_zone":"Asia/Shanghai","target_time_zone":"Europe/London","calendar":"china-mainland","business_hours":16,"business_day_start":"09:00","business_day_end":"17:00","include_start_day":true,"resolution_policy":"reject"} | {"start_local_datetime":"2026-12-24T15:00:00","start_time_zone":"Europe/London","target_time_zone":"Asia/Shanghai","calendar":"uk-england-and-wales","business_hours":8,"business_day_start":"09:00","business_day_end":"17:00","include_start_day":true,"resolution_policy":"reject"} Outputs: calendar, calendar_name, calendar_version, calendar_coverage, tzdb_version, tzdb_package_version, start_local_datetime, start_utc_datetime, counting_started_local_datetime, deadline_utc_datetime, deadline_calendar_zone_datetime, deadline_target_zone_datetime, business_hours_added [hours], business_seconds_added [seconds], elapsed_calendar_hours [hours], working_dates_used, business_segment_count, skipped_date_count, business_segments, skipped_dates, start_adjustments, calendar_sources_used, rules. Formula: deadline = consume business_hours only inside [business_day_start, business_day_end) on dates where the selected versioned calendar reports is_working_day=true; convert each local boundary with pinned IANA tzdb Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/business-hours-deadline with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/business/business-hours-deadline.md

Use this when you know a circle's radius or diameter and need its area, circumference or the other dimension. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the shape is an ellipse (use ellipse), a solid ball (use sphere) or a disc with thickness (use cylinder). What it computes: Computes the area, circumference, diameter and radius of a circle from either its radius or its diameter. Lengths are unit-agnostic: the area is in the square of the input unit. Example user requests: Calculate the area and circumference of a circle with radius 3. | A circle has diameter 10; return its radius, circumference and area. Inputs: radius (number, units, optional); diameter (number, units, optional). Valid input combinations: Provide at least one of radius or diameter. You may provide both when diameter equals 2 × radius; conflicting values are rejected. Complete JSON argument examples: {"radius":3} | {"diameter":10} Outputs: radius [units], diameter [units], circumference [units], area [units²]. Formula: r = radius (or diameter / 2); diameter = 2·r; circumference = 2·π·r; area = π·r² Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/circle with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/geometry/circle.md

Use this when you need to project a savings account, certificate of deposit or investment balance from a starting amount, an annual rate, a term and optional monthly deposits. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when interest is not reinvested (use simple-interest), you need the deposit required to hit a target (use savings-goal), or you are repaying a loan (use loan-payment). What it computes: Computes the future balance of a principal earning compound interest at a chosen compounding frequency, optionally with a fixed deposit at the end of every month, and splits the result into contributions and interest. Inputs: principal (number); annual_rate_percent (number, %); years (number, years); compounding_frequency (enum, optional); monthly_contribution (number, optional). Complete JSON argument examples: {"principal":10000,"annual_rate_percent":5,"years":10,"compounding_frequency":"monthly"} | {"principal":5000,"annual_rate_percent":6,"years":20,"compounding_frequency":"monthly","monthly_contribution":100} Outputs: final_balance, total_contributions, total_interest, effective_annual_rate_percent [%], growth_multiple. Formula: A = principal × (1 + r/n)^(n·years) with r = annual_rate_percent/100 and n periods per year. Contributions: i_m = (1 + r/n)^(n/12) − 1, m = 12·years, FV_contrib = monthly_contribution × ((1 + i_m)^m − 1) / i_m (m × contribution when r = 0). final_balance = A + FV_contrib. Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/compound-interest with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/finance/compound-interest.md

Use this when you need the number of days, weeks or working days between two dates, or a calendar-style 'x years y months z days' difference. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you want to add or subtract a number of days from a date (use add-days), or you need an age with the next birthday (use age). What it computes: Counts the days between two ISO dates and expresses the gap as weeks and days, as a calendar breakdown in years, months and days, and as business days (Monday–Friday, public holidays not excluded). Inputs: start_date (date); end_date (date); include_end_date (boolean, optional). Complete JSON argument examples: {"start_date":"2026-01-01","end_date":"2026-12-25"} | {"start_date":"2025-11-05","end_date":"2026-03-15","include_end_date":true} Outputs: days [days], weeks [weeks], remaining_days [days], weeks_and_days, calendar_years, calendar_months, calendar_days, calendar_text, business_days [days]. Formula: days = end_date − start_date (+1 if include_end_date); weeks = floor(days / 7); remaining_days = days mod 7; business_days = number of Mon–Fri dates in [start_date, end_date) or [start_date, end_date] when inclusive; calendar breakdown = whole years, months, then days borrowed from the month before end_date Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/date-difference with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/date-difference.md

Use this when you need to know how much of a scene is acceptably sharp for given camera settings, or how far sharpness extends in front of and behind the focused subject. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you only need the focus distance that maximises depth of field (use hyperfocal-distance), or you shoot macro above about 0.2× magnification where lens extension and pupil magnification make the thin-lens equations inaccurate. What it computes: Computes the near and far limits of acceptable sharpness, the total depth of field and the hyperfocal distance from focal length, f-number, focus distance and the sensor's circle of confusion, using the standard thin-lens depth-of-field equations. Inputs: focal_length_mm (number, mm); aperture_f (number); focus_distance_m (number, m); sensor (enum, optional); coc_mm (number, mm, optional). Complete JSON argument examples: {"focal_length_mm":50,"aperture_f":2.8,"focus_distance_m":3,"sensor":"full_frame"} | {"focal_length_mm":24,"aperture_f":8,"focus_distance_m":5,"sensor":"full_frame"} Outputs: hyperfocal_m [m], near_limit_m [m], far_limit_m [m], far_limit_text, total_dof_m [m], in_front_of_subject_m [m], behind_subject_m [m], coc_used_mm [mm]. Formula: H = f² / (N·c) + f; near = s·(H − f) / (H + s − 2f); far = s·(H − f) / (H − s) when s < H, otherwise infinity (f = focal_length_mm, N = aperture_f, c = coc_mm, s = focus_distance_m × 1000, all in mm) Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/depth-of-field with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/photography/depth-of-field.md

Use this when you have a set of numeric observations and need its central tendency, spread or quartiles, e.g. the standard deviation of a data set. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need a single percentile or the percentile rank of one value (use percentile), a standardised score (use z-score), or statistics of two paired variables (use correlation or linear-regression). What it computes: Computes summary statistics for a list of numbers: count, sum, mean, median, mode, range, sample and population variance and standard deviation, standard error, coefficient of variation, quartiles (linear interpolation) and skewness. Inputs: values (number_list). Complete JSON argument examples: {"values":[2,4,4,4,5,5,7,9]} | {"values":[4,8,15,16,23,42]} Outputs: count, sum, mean, median, mode, mode_count, min, max, range, sample_variance, sample_std_dev, population_variance, population_std_dev, standard_error, coefficient_of_variation_percent [%], q1, q3, iqr, skewness. Formula: mean = Σx / n; sample_variance = Σ(x − mean)² / (n − 1); population_variance = Σ(x − mean)² / n; standard_error = s / √n; CV% = 100·s / mean; quartile at p: rank = p·(n − 1), value = x(⌊rank⌋) + (rank − ⌊rank⌋)·(x(⌊rank⌋+1) − x(⌊rank⌋)) on sorted data; skewness G1 = n / ((n − 1)(n − 2)) · Σ((x − mean) / s)³ Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/descriptive-statistics with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/statistics/descriptive-statistics.md

Use this when you need an exact result of an operation on two fractions (e.g. 3/4 + 1/6), including mixed numbers such as 1 1/2, rather than a rounded decimal. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you only want to reduce a single fraction or convert it to a decimal or percent (use fraction-simplifier), or you need the least common denominator of several denominators (use gcd-lcm). What it computes: Adds, subtracts, multiplies or divides two fractions, mixed numbers, whole numbers or decimals with exact integer arithmetic, returning the result in lowest terms, as a mixed number and as a decimal, with the intermediate steps. Inputs: fraction_a (string); fraction_b (string); operation (enum, optional). Complete JSON argument examples: {"fraction_a":"3/4","fraction_b":"1/6","operation":"add"} | {"fraction_a":"2 1/3","fraction_b":"5/6","operation":"subtract"} Outputs: result, mixed_number, numerator, denominator, decimal, working. Formula: a/b + c/d = (a·(L/b) + c·(L/d)) / L with L = lcm(b, d), a/b − c/d likewise; a/b × c/d = (a·c) / (b·d); a/b ÷ c/d = (a·d) / (b·c); the result is divided by gcd(numerator, denominator) Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/fraction-arithmetic with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/math/fraction-arithmetic.md

Use this when you need the straight-line distance between two GPS coordinates or cities, e.g. for flight distance, range checks or geofencing. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need road distance, or ellipsoidal accuracy better than about 0.5 % (use a geodesic method such as Vincenty or Karney on WGS-84); for bearings and compass points use compass-bearing. What it computes: Computes the great-circle (as-the-crow-flies) distance between two points on a spherical Earth with the haversine formula, in kilometres, miles and nautical miles, together with the initial bearing, compass direction and the midpoint of the route. Inputs: lat1 (number, °); lon1 (number, °); lat2 (number, °); lon2 (number, °). Complete JSON argument examples: {"lat1":-33.8688,"lon1":151.2093,"lat2":35.6762,"lon2":139.6503} | {"lat1":50.06639,"lon1":-5.71472,"lat2":58.64389,"lon2":-3.07} Outputs: distance_km [km], distance_miles [mi], distance_nautical_miles [nmi], central_angle_degrees [°], initial_bearing_degrees [°], compass_direction, midpoint_lat [°], midpoint_lon [°]. Formula: a = sin²(Δφ/2) + cos φ1 · cos φ2 · sin²(Δλ/2); c = 2 · atan2(√a, √(1−a)); d = R · c with R = 6371.0088 km; θ = atan2(sin Δλ · cos φ2, cos φ1 · sin φ2 − sin φ1 · cos φ2 · cos Δλ) Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/haversine-distance with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/time/haversine-distance.md

Use this when you need the energy of motion of an object of known mass and speed (vehicle, projectile, ball), for example to compare impact or braking energies. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when rotation contributes significantly (rotational energy ½·I·ω² is not included), speeds approach the speed of light (relativistic formula needed), or you need energy from height (use potential-energy). What it computes: Computes the translational kinetic energy of a moving mass from KE = ½·m·v², reported in joules, kilojoules, kilowatt-hours and kilocalories. Inputs: mass_kg (number, kg); velocity_m_s (number, m/s). Complete JSON argument examples: {"mass_kg":1200,"velocity_m_s":25} | {"mass_kg":0.145,"velocity_m_s":40} Outputs: kinetic_energy_j [J], kinetic_energy_kj [kJ], kinetic_energy_kwh [kWh], kinetic_energy_kcal [kcal], velocity_km_h [km/h]. Formula: KE = ½ × mass_kg × velocity_m_s²; kJ = J / 1000; kWh = J / 3,600,000; kcal = J / 4184 Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/kinetic-energy with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/physics/kinetic-energy.md

Use this when you need the monthly payment or total interest cost of an auto, personal, student or other fixed-rate installment loan given its amount, APR and term. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need property tax, insurance and HOA in the payment (use mortgage-payment), or you know the payment and want the payoff time (use debt-payoff). What it computes: Computes the level monthly payment of a fully amortizing fixed-rate loan from principal, annual rate and term, plus the total paid and total interest over the life of the loan. Example user requests: For a 100000 loan at 6% fixed for 5 years, calculate the monthly payment and total interest. | What will I pay each month on a 420000 loan at 6.15% for 25 years? | 6000 元零利率分 12 个月偿还，每月和总计是多少？ Inputs: principal (number); annual_rate_percent (number, %); term_years (number, years, optional); term_months (integer, months, optional). Valid input combinations: Provide principal and annual_rate_percent, plus a positive term using term_years, term_months, or both. When both term fields are present they are added together. Complete JSON argument examples: {"principal":200000,"annual_rate_percent":6,"term_years":30} | {"principal":25000,"annual_rate_percent":7,"term_months":60} Outputs: monthly_payment, number_of_payments, total_payment, total_interest, payoff_summary. Formula: i = annual_rate_percent / 1200; n = 12·term_years + term_months; monthly_payment = principal × i / (1 − (1 + i)^−n); if i = 0, monthly_payment = principal / n. total_payment = monthly_payment × n; total_interest = total_payment − principal. Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/loan-payment with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/finance/loan-payment.md

Use this when you have a chemical formula and need its molar mass (molecular weight), the number of atoms of each element, or its elemental mass-percent composition. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you already know the molar mass and want to convert between grams and moles (use moles-mass) or need a solution concentration (use molarity). What it computes: Parses a chemical formula (including brackets, nested groups and hydrates) and sums IUPAC 2021 standard atomic weights to give the molar mass in g/mol, plus the atom count and mass-percent composition of each element. Inputs: formula (string). Complete JSON argument examples: {"formula":"C6H12O6"} | {"formula":"CuSO4·5H2O"} Outputs: molar_mass_g_mol [g/mol], molecular_mass_da [Da], atom_count, element_count, composition. Formula: molar_mass = Σ (atomic_weight_i × count_i); mass_fraction_percent_i = 100 × atomic_weight_i × count_i / molar_mass Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/molar-mass with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/chemistry/molar-mass.md

Use this when you want the monthly cost of buying a home with a fixed-rate mortgage, including escrowed taxes and insurance, or the total interest over the loan. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the loan is adjustable-rate or interest-only, or you only need the payment on a plain loan amount (use loan-payment). What it computes: Computes the monthly principal-and-interest payment of a fixed-rate mortgage from home price, down payment, rate and term, then adds property tax, home insurance and HOA dues to give the full monthly housing payment and lifetime interest. Inputs: home_price (number); down_payment (number, optional); annual_rate_percent (number, %); term_years (number, years, optional); annual_property_tax (number, optional); annual_home_insurance (number, optional); monthly_hoa (number, optional). Complete JSON argument examples: {"home_price":250000,"down_payment":50000,"annual_rate_percent":6,"term_years":30,"annual_property_tax":3000,"annual_home_insurance":1200} | {"home_price":400000,"down_payment":80000,"annual_rate_percent":6.5,"term_years":30} Outputs: loan_amount, loan_to_value_percent [%], monthly_principal_and_interest, monthly_property_tax, monthly_insurance, monthly_hoa_fee, total_monthly_payment, number_of_payments, total_interest, total_of_payments, payoff_summary. Formula: loan_amount = home_price − down_payment; i = annual_rate_percent / 1200; n = 12·term_years; P&I = loan_amount × i / (1 − (1 + i)^−n) (loan_amount / n if i = 0); total_monthly_payment = P&I + annual_property_tax/12 + annual_home_insurance/12 + monthly_hoa. Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/mortgage-payment with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/finance/mortgage-payment.md

Use this when you need a percentage of a value, the percentage one value represents of another, or the base value that a part and its percentage imply. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need the percentage change between two values (use percentage-change), a price after a percentage discount (use discount) or a tax amount (use sales-tax). What it computes: Solves the three basic percentage questions (a percentage of a number, what percentage one number is of another, and the whole behind a known part and percentage). Always returns the part, the whole and the percent. Inputs: mode (enum, optional); x (number); y (number). Complete JSON argument examples: {"mode":"percent_of","x":15,"y":240} | {"mode":"is_what_percent","x":30,"y":120} Outputs: result, sentence, part, whole, percent [%]. Formula: percent_of: result = x / 100 × y. is_what_percent: result = x / y × 100. percent_of_what: result = x / (y / 100). In every mode part = percent × whole / 100. Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/percentage with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/math/percentage.md

Use this when you have a starting and an ending value and need the percentage increase or decrease, or a symmetric percent difference between two comparable values. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you need a percentage of a number (use percentage), an annualised growth rate over several years (use cagr) or an investment return (use roi). What it computes: Computes the relative change from an old value to a new value as a percentage, the signed absolute change, the new/old ratio and the symmetric percent difference. Inputs: old_value (number); new_value (number). Complete JSON argument examples: {"old_value":50,"new_value":65} | {"old_value":80,"new_value":60} Outputs: change_percent [%], absolute_change, direction, ratio, percent_difference [%]. Formula: change_percent = (new_value − old_value) / |old_value| × 100; percent_difference = |new_value − old_value| / ((|new_value| + |old_value|) / 2) × 100 Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/percentage-change with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/math/percentage-change.md

Use this when you know a distance and the time it took (or a target time) and need the pace, the equivalent speed, or the time that pace gives over standard race distances. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you want a realistic prediction of a longer race from a shorter one (pace slows with distance; use race-time-predictor), or you only need to convert between pace and speed units (use pace-converter). What it computes: Computes running pace in min/km and min/mile and speed in km/h and mph from a distance and elapsed time, and projects the finish time for 5 km, 10 km, half marathon and marathon at that constant pace. Inputs: distance (number); distance_unit (enum, optional); time (string). Complete JSON argument examples: {"distance":10,"distance_unit":"km","time":"50:00"} | {"distance":5,"distance_unit":"mi","time":"45:00"} Outputs: pace_min_per_km [min:sec/km], pace_min_per_mile [min:sec/mi], pace_seconds_per_km [s/km], speed_kmh [km/h], speed_mph [mph], distance_km [km], time_5k [h:mm:ss], time_10k [h:mm:ss], time_half_marathon [h:mm:ss], time_marathon [h:mm:ss]. Formula: pace_s_per_km = time_seconds / distance_km; pace_s_per_mile = pace_s_per_km × 1.609344; speed_kmh = 3600 / pace_s_per_km; speed_mph = speed_kmh / 1.609344; time(D) = pace_s_per_km × D for D = 5, 10, 21.0975, 42.195 km Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/running-pace with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/fitness/running-pace.md

Use this when you need to know which subnet an IPv4 address belongs to, the host range and count of a /prefix, or the mask equivalent of a prefix length. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the address is IPv6, you want to split a block into several subnets (VLSM planning), or you only need a number in binary or hex (use base-converter). What it computes: Computes the network and broadcast addresses, subnet and wildcard masks, first and last host, usable and total addresses, address class and RFC 1918 private status for an IPv4 address in CIDR notation or with a dotted subnet mask, using 32-bit unsigned arithmetic. Inputs: cidr (string). Complete JSON argument examples: {"cidr":"192.168.1.10/26"} | {"cidr":"10.0.0.0 255.0.0.0"} Outputs: ip_address, cidr_notation, network_address, broadcast_address, subnet_mask, wildcard_mask, prefix_length [bits], host_bits [bits], first_host, last_host, usable_hosts, total_addresses, ip_class, is_private, address_scope, binary_mask, binary_address, ip_integer. Formula: mask = 2^32 − 2^(32 − prefix); network = ip AND mask; broadcast = network OR NOT mask; total = 2^(32 − prefix); usable = total − 2 (prefix ≤ 30), 2 (prefix 31), 1 (prefix 32) Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/subnet-calculator with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/developer/subnet-calculator.md

Use this when you want to test whether a sample mean differs from a hypothesised value, whether two independent groups have different means, or whether paired before/after measurements changed. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the data are proportions or counts (use proportion-z-test or chi-square-test), you have three or more groups (ANOVA), or you already have t and df and only need the p-value (use p-value). What it computes: Runs a one-sample, Welch two-sample (unequal variances) or paired Student t-test from raw samples or summary statistics (mean, SD, n), returning t, degrees of freedom, two- and one-sided p-values, the confidence interval and the decision at the chosen alpha. Example user requests: Run a one-sample t-test for [102, 98, 105, 101, 104] against a mean of 100. | Compare two independent samples with Welch's t-test from their means, sample SDs and sample sizes. | Run a paired t-test on these before and after measurements in matching order. Inputs: mode (enum, optional); sample_a (number_list, optional); sample_b (number_list, optional); mean_a (number, optional); sd_a (number, optional); n_a (integer, optional); mean_b (number, optional); sd_b (number, optional); n_b (integer, optional); hypothesized_mean (number, optional); alpha (number, optional). Valid input combinations: one_sample: sample_a, or all of mean_a + sd_a + n_a. two_sample (also the default when mode is omitted): one complete raw-or-summary input for A and one for B. paired: both sample_a + sample_b, or paired-difference summary mean_a + sd_a + n_a. Do not mix a raw sample with its summary fields. Complete JSON argument examples: {"mode":"two_sample","sample_a":[5.1,4.9,5.6,5.8,6],"sample_b":[4.2,4.8,4.4,4.6,4.5]} | {"mode":"two_sample","mean_a":5.48,"sd_a":0.47117,"n_a":5,"mean_b":4.5,"sd_b":0.23452,"n_b":5} | {"mode":"one_sample","sample_a":[102,98,105,101,104],"hypothesized_mean":100} | {"mode":"paired","sample_a":[1.9,0.8,1.1,0.1,-0.1,4.4,5.5,1.6,4.6,3.4],"sample_b":[0.7,-1.6,-0.2,-1.2,-0.1,3.4,3.7,0.8,0,2]} | {"mode":"paired","mean_a":1.58,"sd_a":1.23042,"n_a":10} Outputs: test, mean_a, mean_b, mean_difference, standard_error, t_statistic, degrees_of_freedom, p_value_two_sided, p_value_one_sided, t_critical, ci_lower, ci_upper, significant, decision. Formula: one_sample: t = (x̄ − μ0) / (s / √n), df = n − 1. paired: same on the differences d = a − b. two_sample (Welch): t = (x̄a − x̄b − μ0) / √(sa²/na + sb²/nb), df = (sa²/na + sb²/nb)² / ((sa²/na)²/(na − 1) + (sb²/nb)²/(nb − 1)). p = P(|T_df| ≥ |t|); CI = estimate ± t(1 − alpha/2, df) × SE Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/t-test with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/statistics/t-test.md

Use this when you need daily maintenance calories for an adult, or calorie targets for a mild/standard deficit or surplus. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when the person is a child, pregnant or breastfeeding, or you only need the resting rate (use bmr). What it computes: Estimates total daily energy expenditure from Mifflin-St Jeor BMR and an activity level, and derives calorie targets for maintaining, losing or gaining weight. Inputs: sex (enum); weight_kg (number, kg); height_cm (number, cm); age_years (number, years); activity_level (enum, optional). Complete JSON argument examples: {"sex":"male","weight_kg":70,"height_cm":175,"age_years":30,"activity_level":"moderate"} Outputs: bmr_kcal_per_day [kcal/day], activity_multiplier, tdee_kcal_per_day [kcal/day], mild_loss_kcal_per_day [kcal/day], loss_kcal_per_day [kcal/day], mild_gain_kcal_per_day [kcal/day], gain_kcal_per_day [kcal/day]. Formula: TDEE = BMR(Mifflin-St Jeor) × activity_multiplier; targets = TDEE ± 250 or ± 500 kcal/day Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/tdee with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/health/tdee.md

Use this when you need to add a gratuity to a restaurant, delivery or service bill and optionally divide the total among several people. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when people pay for different items or unequal shares (use bill-split), or you need to add sales tax rather than a tip (use sales-tax). What it computes: Computes the tip from a bill amount and tip percentage, the total including tip, and the per-person share when the bill is split evenly. Inputs: bill_amount (number); tip_percent (number, %, optional); split_between (integer, optional). Complete JSON argument examples: {"bill_amount":85.5,"tip_percent":18,"split_between":3} | {"bill_amount":42,"tip_percent":20} Outputs: tip_amount, total_amount, total_per_person, tip_per_person, bill_per_person. Formula: tip_amount = bill_amount × tip_percent / 100; total_amount = bill_amount + tip_amount; per person = value / split_between Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/tip with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/finance/tip.md

Use this when you need a Plum Blossom hexagram cast for a moment or from numbers, with the upper/lower trigram arithmetic, the moving line and the 体/用 five-element reading laid out step by step. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you already have six lines from coins or yarrow (use liuyao for a 六爻 chart or hexagram-change for plain line changes), or you only want a hexagram's text and structure (use hexagram-lookup). What it computes: Casts an I Ching hexagram by the Plum Blossom (Meihua Yishu) method of Shao Yong from the lunar year, month, day and hour (年月日时起卦) or from two or three given numbers, then derives the moving line, changed hexagram (之卦), nuclear hexagram (互卦), the 体 (Ti, self) and 用 (Yong, matter) trigrams and their five-element relations. Inputs: method (enum, optional); date (date, optional); time (string, optional); number_1 (integer, optional); number_2 (integer, optional); number_3 (integer, optional); add_hour_to_moving_line (boolean, optional). Valid input combinations: time_method needs date/time only; two_numbers requires number_1 + number_2; three_numbers requires number_1 + number_2 + number_3. Complete JSON argument examples: {"method":"time_method","date":"2026-09-24","time":"14:30"} | {"method":"two_numbers","number_1":3,"number_2":7,"date":"2026-09-24","time":"12:00"} Outputs: method_used, lunar_date, upper_trigram, lower_trigram, original_hexagram, original_lines, moving_line, moving_line_name, changed_hexagram, nuclear_hexagram, ti_trigram, yong_trigram, ti_element, yong_element, yong_ti_relation, nuclear_relations, changed_relation, ti_seasonal_strength, calculation_trace, reading_hint, disclaimer. Formula: Time method: year = branch number of the lunar year (子 = 1 … 亥 = 12), month = lunar month, day = lunar day, hour = 时辰 number (子 = 1 … 亥 = 12); upper = (year + month + day) mod 8, lower = (year + month + day + hour) mod 8, moving line = (year + month + day + hour) mod 6 (remainder 0 → 8 or 6); trigram numbers in earlier-heaven order 乾1 兑2 离3 震4 巽5 坎6 艮7 坤8. Two numbers: upper = number_1 mod 8, lower = number_2 mod 8, moving = (number_1 + number_2 [+ hour]) mod 6. Three numbers: moving = number_3 mod 6. 体 = trigram without the moving line, 用 = trigram with it; relations by the five-element generating (木→火→土→金→水) and controlling (木→土→水→火→金) cycles. Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/meihua-yishu with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/yijing/meihua-yishu.md

Use this when you need a deterministic Argentina Argentina nationwide national holidays and published tourism non-working days for 2026 result. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when provincial, municipal, employer, bank, exchange, school, sector and religion-specific schedules are not generalized; regional one-off holidays are not included in this nationwide default. What it computes: Checks a date against the Saturday-Sunday weekend baseline and exact 2026-2026 authority events. Example user requests: Argentina: Argentina national holiday. Inputs: date (date). Complete JSON argument examples: {"date":"2026-05-25"} Outputs: territory, territory_name, weekday, is_working_day, day_type, holiday_names, holiday_kinds, holiday_details, calendar_scope, holiday_policy, substitute_day_policy, calendar_profile, dataset_version, sources. Formula: is_working_day = not an official Saturday/Sunday weekend date and no exact authority event Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/argentina-working-day with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/argentina-working-day.md

Use this when you need a deterministic Austria Austria nationwide statutory public holidays for 2026-2027 result. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when nationwide statutory holiday list only. Werktag is not uniform across Austrian legal domains; Saturday treatment, provincial patron days, school, bank, employer and sector schedules are not inferred. What it computes: Checks a date against the Saturday-Sunday weekend baseline and exact 2026-2027 authority events. Example user requests: Austria: Austrian National Day. | Austria: Ordinary weekday. Inputs: date (date). Complete JSON argument examples: {"date":"2026-10-26"} | {"date":"2026-10-27"} Outputs: territory, territory_name, weekday, is_working_day, day_type, holiday_names, holiday_kinds, holiday_details, calendar_scope, holiday_policy, substitute_day_policy, calendar_profile, dataset_version, sources. Formula: is_working_day = not an official Saturday/Sunday weekend date and no exact authority event Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/austria-public-working-day with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/austria-public-working-day.md

Use this when you need a state/territory-wide Australian public-holiday result. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you do not know the state/territory, or you need a local council, regional, employer, exchange or industry calendar. What it computes: Checks an Australian date for a required state or territory using the Fair Work Ombudsman 2026-2027 public-holiday tables and explicit scope limitations. Example user requests: Is 2026-04-27 a working day in NSW? | Check 2027-12-27 in Victoria. Inputs: date (date); division (enum). Complete JSON argument examples: {"date":"2026-04-27","division":"nsw"} Outputs: territory, territory_name, division, division_name, weekday, is_working_day, day_type, weekend_days, holiday_names, holiday_observed, limited_or_part_day_events, calendar_scope, calendar_profile, source_quality, regional_policy, dataset_version. Formula: is_working_day = CLDR AU weekend baseline and no state/territory-wide full-day public holiday Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/australia-working-day with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/australia-working-day.md

Use this when you need a deterministic Bangladesh Bangladesh 2026 government public-office holiday schedule plus later election-period national closures result. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when government/public-office schedule only; private-employer, bank, school, industrial-zone, essential-service, regional hill-district, optional-religious and later unlisted ad hoc schedules are not inferred. February 10 is not included because the reported later holiday was industrial-zone specific. Lunar dates may be revised by a later official notice. What it computes: Checks a date against the Friday-Saturday weekend baseline and exact 2026-2026 authority events. Example user requests: Bangladesh: Election-period special holiday. | Bangladesh: Eid-ul-Adha period. Inputs: date (date). Complete JSON argument examples: {"date":"2026-02-11"} | {"date":"2026-05-31"} Outputs: territory, territory_name, weekday, is_working_day, day_type, holiday_names, holiday_kinds, holiday_details, calendar_scope, holiday_policy, substitute_day_policy, calendar_profile, dataset_version, sources. Formula: is_working_day = not an official Friday/Saturday weekend date and no exact authority event Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/bangladesh-public-working-day with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/bangladesh-public-working-day.md

Use this when you need a deterministic Belgium Belgium ten statutory private-sector public holidays for 2026-2027 result. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when private-sector statutory core only; substitute dates, public-service/community/regional holidays, sector agreements, employer, school, bank and municipal schedules are not inferred. What it computes: Checks a date against the Saturday-Sunday weekend baseline and exact 2026-2027 authority events. Example user requests: Belgium: Belgian National Day. | Belgium: Ordinary weekday. Inputs: date (date). Complete JSON argument examples: {"date":"2026-07-21"} | {"date":"2026-07-22"} Outputs: territory, territory_name, weekday, is_working_day, day_type, holiday_names, holiday_kinds, holiday_details, calendar_scope, holiday_policy, substitute_day_policy, calendar_profile, dataset_version, sources. Formula: is_working_day = not an official Saturday/Sunday weekend date and no exact authority event Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/belgium-public-working-day with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/belgium-public-working-day.md

Use this when you need a deterministic Bulgaria Bulgaria 2026 nationwide rest-day facts with explicit Monday-Friday planning baseline result. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when bulgaria 2026 nationwide statutory holidays, observed non-attendance days and January 2 one-off rest over an explicitly selected Monday-Friday planning baseline. November 1 is education-only and does not add general rest. No personal, shift, school, employer, bank/exchange, optional religious-leave, payroll or legal-deadline schedule is computed. Future years and additional local/sector closures are unsupported. What it computes: Checks a date against the Saturday-Sunday weekend baseline and exact 2026-2026 authority events. Requires explicit mon_fri_planning; education-only holidays do not create general rest. Example user requests: Bulgaria: One-off euro transition rest, not statutory holiday. | Bulgaria: May 24 Sunday replacement. | Bulgaria: No nationwide school-holiday substitute. Inputs: date (date); work_schedule (enum). Complete JSON argument examples: {"date":"2026-01-02","work_schedule":"mon_fri_planning"} | {"date":"2026-05-25","work_schedule":"mon_fri_planning"} | {"date":"2026-11-02","work_schedule":"mon_fri_planning"} Outputs: territory, territory_name, weekday, is_working_day, day_type, holiday_names, holiday_kinds, holiday_details, calendar_scope, holiday_policy, substitute_day_policy, calendar_profile, dataset_version, sources, work_schedule, is_statutory_holiday, is_observed_non_attendance_day, is_one_off_non_attendance_day, is_education_only_holiday, observed_for_dates, payroll_scope. Formula: planning_workday = weekday AND no nationwide statutory/observed/one-off rest event Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/bulgaria-public-working-day with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/everyday/bulgaria-public-working-day.md