Business Days Calculator

A business day is any weekday your workplace, bank, or school is open, usually Monday through Friday. Saturdays, Sundays, and public holidays are not business days, so a promise of "5 business days" almost always spans a full calendar week.

This calculator works in two modes. Days between dates counts the business days inside a range, which is what payroll, leave, and project planning usually need. Add business days walks forward from a start date and lands on the deadline, which is what contracts and shipping estimates need. If you only need the plain time between two moments, the time duration calculator measures hours and minutes instead.

The rule is one subtraction, and the calculator shows its work every time. Here is the exact formula it runs.

Business Days = Total Calendar Days − Weekend Days − Holidays on Weekdays

Total Calendar Days is the count of days from the start date to the end date. The start date is always counted. The end date counts only when the "Include end date" box is ticked. Weekend Days is the count of Saturdays and Sundays in that span. Holidays on Weekdays is the count of the holiday dates you listed that fall inside the span on Monday to Friday. A holiday that lands on a weekend is ignored, because that day was already skipped.

In Add business days mode the formula flips direction. Result Date = Start Date + N Business Days, counting forward one business day at a time and skipping weekends and listed holidays. The start date is never counted. Day 1 is the first business day after it.

Count the business days from Monday, March 2, 2026 to Friday, March 20, 2026, with the end date included and no holidays listed. Work it through by hand.

Step 1. Total calendar days. March 2 to March 20, both dates included, is 19 days. Step 2. Weekend days. March 7 to 8 and March 14 to 15 are the two weekends inside the range, so 4 weekend days. Step 3. Holidays. None were listed, so 0. Step 4. Subtract. 19 − 4 − 0 = 15 business days.

1. Choose the Days between dates tab or the Add business days tab.
2. For a range, pick the start and end dates, tick Include end date if the last day counts, and optionally list holidays one per line.
3. For a deadline, pick the start date, enter the number of business days to add, and optionally list holidays.
4. Press Calculate to see the result, the supporting numbers, and the steps. Press Reset to clear the form and start over.

The "Include end date" box is the choice that trips people up. Leave it ticked and both endpoints count, which matches payroll and leave math where June 1 to June 5 is five days. Untick it and the end date drops out, which matches deadline math that counts the working days leading up to a date.

When you are unsure, read the wording of the policy or contract. "Through Friday" usually includes Friday, while "within 10 business days of Monday" usually does not count Monday. The calculator states which convention it used in the steps, so the answer is always auditable.

The calculator ships with no built-in holiday calendar, because public holidays differ by country, state, and year. You list your own dates in YYYY-MM-DD form, one per line, for example 2026-12-25. A line that is not a real date is flagged by name instead of silently changing the answer.

Only holidays that fall on a weekday change the count. If Christmas falls on a Saturday, it is ignored, because Saturday was already skipped. If a holiday falls outside your date range, it is ignored too. The result names how many holidays were actually excluded, so a zero there tells you to check your list. For calendar-day math that ignores the work week entirely, the date calculator adds or subtracts plain days.

Add business days when a contract, shipment, or SLA is quoted in working time. The start date is never counted, so "1 business day after Friday" is Monday, not Friday itself. The walk skips weekends and your listed holidays one day at a time.

Take Friday, December 18, 2026, add 10 business days, and list 2026-12-25 and 2027-01-01 as holidays. Day 1 is Monday, December 21. Counting forward gives December 21, 22, 23, and 24, then skips Christmas Day, continues through December 28, 29, 30, and 31, skips New Year's Day, and reaches day 10 on Tuesday, January 5, 2027. The span is 18 calendar days with 6 weekend days and 2 holidays skipped.