Business Days Calculator

How many working days are there between two dates? Count Monday–Friday (or any weekly pattern), subtract holidays, and see exactly which days were removed.

How business days are counted

A business day is any date that survives two filters. First the date has to fall on a weekday you have ticked as working. Then it has to avoid the holiday list. Everything else is removed:

business days = calendar days − off-week days − federal holidays − extra closures

The loop is deliberately simple: we walk one calendar day at a time from the start date to the end date and count what passes both filters. That is slower than a formula based on week arithmetic, but it is the only way to stay correct once holidays enter the picture — holidays land on different weekdays every year, so there is no clean closed-form shortcut.

Dates are handled in UTC rather than local time. Counting in local time breaks twice a year wherever daylight saving applies, because one day per year is only 23 hours long and the difference divided by 24 hours lands a fraction short. UTC avoids that entirely.

A worked example

Take Thu 1 January 2026 to Sat 31 January 2026 inclusive, with a Monday–Friday week and US federal holidays switched on.

The span is 31 calendar days. Of those, 22 fall on a Monday through Friday and 9 are weekend days (5 Saturdays and 4 Sundays). January 2026 contains two federal holidays: New Year's Day on Thursday 1 January and Martin Luther King Jr. Day on Monday 19 January — both fall on working days, so both count as removals. Result: 22 − 2 = 20 business days.

Switch the end date off and the answer stays 20: 31 January is a Saturday, so removing it takes away a day that was never in the working-day pool. Inclusive versus exclusive only changes the result when the end date is itself a working day — end the same span on Friday 30 January with exclusive counting and you drop a real working day, leaving 19.

Start instead on 2 January and keep 31 January as the end date: New Year's Day now falls outside the span, so only MLK Day is subtracted — 30 calendar days, 21 weekdays, 1 holiday, giving 20 business days again.

Which holidays are excluded

The built-in list follows the US federal schedule, using the same observance rules the government applies: when a fixed-date holiday falls on a Saturday it is observed on the preceding Friday, and when it falls on a Sunday it is observed on the following Monday.

• Fixed dates: New Year's Day (1 Jan), Juneteenth (19 Jun), Independence Day (4 Jul), Veterans Day (11 Nov), Christmas Day (25 Dec).
• Day-of-week rules: Martin Luther King Jr. Day (3rd Mon Jan), Washington's Birthday (3rd Mon Feb), Memorial Day (last Mon May), Labor Day (1st Mon Sep), Columbus Day (2nd Mon Oct), Thanksgiving (4th Thu Nov).
• Start dates honoured: MLK Day from 1986 and Juneteenth from 2022 are not applied to earlier years.

Limitations

This is a US-centric count. State holidays (such as Texas Rifles Day or Virginia's Lee-Jackson Day) and non-US public holidays are not included — list them in the extra-dates field instead. Bank or religious calendars that move with the lunar cycle are not modelled either.

Half-days and holiday-eve early closes are whole days here. A contract that says "ten business days" may also start counting on the following working day rather than on the date of the agreement itself, and some jurisdictions exclude the start day while others exclude holidays only if they fall within the term. When the date genuinely matters legally, check the wording of the contract and confirm against an official calendar.

Frequently asked questions

Last updated Oct 7, 2026 — holiday rules change, so double-check against an official calendar before relying on a count.

For general planning only. Contract deadlines are governed by the wording of the contract, not by this count — see our disclaimer.

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