Business Days Calculator
Calculate a future or past date by adding or subtracting a number of business days (Mon–Fri).
Did this tool work for you?
How to use this calculator
- 1
Enter the start date.
- 2
Enter the number of business days to count.
- 3
Choose forward (future date) or backward (past date).
- 4
The result date and day of the week appear instantly.
Frequently asked questions
Does the start date count as day 1?
No, it is day 0. Day 1 is the next weekday after it. Starting Tuesday November 3, 2026 and adding 10 business days lands on Tuesday November 17, which is 14 calendar days later.
What if the start date is a Saturday or Sunday?
The count still begins at the following weekday. Adding 1 business day to Saturday November 7, 2026 gives Monday November 9, only 2 calendar days later. The weekend start is simply skipped over and not treated as a working day.
What happens if I enter 0 business days?
The start date is returned unchanged, even if it is a weekend. Starting from Saturday November 7, 2026 with 0 days shows Saturday November 7, 2026. For any non-zero amount the result always falls on a weekday.
Are public holidays skipped?
No, only Saturdays and Sundays are skipped. If a bank holiday lies in the window, the real deadline will be later, so add one more business day for each holiday that falls on a weekday.
How do I count backwards from a deadline?
Set Direction to Backward and enter the deadline as the start date. Counting 5 business days back from Friday December 18, 2026 gives Friday December 11, 2026, a span of 7 calendar days.
How are fractions and negative numbers treated?
The number is rounded down to a whole day and its sign is ignored, with the Direction selector deciding which way to go. 2.9 business days from Tuesday November 3, 2026 gives Thursday November 5, which is 2 business days. Entering −5 with Forward still moves forward 5.
Does a contract’s “within 5 business days” match this count?
Not necessarily. Some wording counts the day of the event as day 1, some starts the next day, and some define business days with local holidays or bank hours. Use the calculator for the arithmetic and check the contract definition for how the clock starts.
Business days calculator — add or subtract weekdays from a date
Weekday arithmetic
Adding business days means stepping forward one calendar day at a time and only counting the steps that land on Monday to Friday. Ten business days from a Tuesday is therefore exactly two calendar weeks later, because every full week holds five. The start date is day zero, so asking for one business day from a Friday gives the following Monday, three calendar days away. The same step from a Saturday or a Sunday also lands on Monday, because the weekend days never count towards the total.
Worked examples
Business-day results from fixed dates. The columns show Start, Move, Result and Calendar days, one line per case.
| Start | Move | Result | Calendar days |
|---|---|---|---|
| Tue 2026-11-03 | +10 | Tue November 17, 2026 | 14 |
| Tue 2026-11-03 | +30 | Tue December 15, 2026 | 42 |
| Fri 2026-11-06 | +1 | Mon November 9, 2026 | 3 |
| Sat 2026-11-07 | +1 | Mon November 9, 2026 | 2 |
| Sat 2026-11-07 | 0 | Sat November 7, 2026 | 0 |
| Fri 2026-12-18 | −5 | Fri December 11, 2026 | 7 |
Shortcuts for round numbers
Multiples of five are easy to check mentally. Starting on a weekday, 5 business days is the same weekday next week, 10 is two weeks, and 30 is six weeks, which is why 30 business days from November 3 is 42 calendar days away. For other numbers the answer shifts by two extra days each time the count crosses a weekend, so the calculator is more reliable than counting on a calendar.
Where holidays fit in
The calculator skips only Saturdays and Sundays. A 10-business-day period that spans a Monday public holiday has one fewer real working day in it, so the true end date is one weekday later. If your jurisdiction lists several holidays in the period, count them on a calendar and push the result forward by that many weekdays.
Deadlines and start-of-clock rules
Shipping estimates, payment terms and notice periods all quote business days, but they disagree about whether the clock starts on the day of the event or the next day. This tool treats the start date as day zero. If your document counts the event day as day one, enter the day before the event as the start date, or subtract one from the number of days. Whatever convention you pick, write it next to the result so the person reading the deadline knows how it was counted.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →