Business Days Calculator
Count working days between two dates, skipping weekends and optional US holidays, with the counting conventions that produce different answers.
business days
A year does not have 260 working days
Counting weekdays across 2000–2100, before any public holidays are taken off:
| Weekdays in the year | How many years | |
|---|---|---|
| 260 | 25 of 101 | |
| 261 | 62 of 101 | |
| 262 | 14 of 101 |
A spread of 2 full days, driven entirely by which weekday the year starts on and whether it is a leap year. This year has 261. No year between 1950 and 2150 falls outside 260–262, so the variation is small but it is never zero.
Which means a day rate computed as salary ÷ 260 is wrong in about three quarters of years, and by up to two days of pay. The same applies to any capacity plan, sprint count or billing forecast built on a round number.
The exact long-run average is 260.8875 — which has to equal 365.2425 × 5 ÷ 7, since the Gregorian year averages 365.2425 days and five sevenths of any long stretch are weekdays. It does, to the last decimal place, which is a decent sign the count is right.
How to use
- Enter the start and end dates.
- Choose whether to include holidays.
- Decide whether the start date counts.
- Read the working day total.
Frequently asked questions
Does the count include the start and end dates?
That depends on the convention, and it is the main reason two people counting the same period get different answers. Deadlines expressed in business days usually start counting from the day after the trigger event, so a five-day deadline set on Monday falls on the following Monday.
Which holidays are excluded?
US federal holidays by default, though these are not universal — private employers are not required to observe them, and state and local holidays vary considerably. If a contract depends on the count, it should say explicitly which calendar applies.
Why does a holiday falling at the weekend still matter?
Because most US federal holidays are observed on the nearest weekday when they land on a Saturday or Sunday, moving the closure to a day that would otherwise have been a working day. The count changes accordingly, which is easy to miss.
Do business days mean the same thing internationally?
No. Weekends differ — several countries in the Middle East observe Friday and Saturday — and public holidays differ enormously. A calculation assuming a Monday-to-Friday week with US holidays is simply wrong for much of the world.
How are moveable holidays handled?
By calculation rather than a fixed list, since dates like Thanksgiving are defined by position in the month and Easter by a lunar formula. A hard-coded list of dates works until it silently stops, which is why computing them is the safer approach.
What about partial days and time zones?
Business day counts ignore both, which is usually fine and occasionally not. Where a deadline falls at a specific hour, or where parties are in different zones, the count alone does not settle when something is actually due.
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