Add or subtract days from a date

Result = start date ± N daysFor business days, Saturdays and Sundays are passed over, and federal holidays too when that box is ticked.

1. Calendar days90 days after January 1, 2026: 30 days to January 31, 28 more to February 28, 31 more to March 31, and 1 more lands on April 1.
2. Business days5 business days after Friday, October 2, 2026 is Friday, October 9. With federal holidays skipped, 6 business days later is Tuesday, October 13, because Columbus Day is Monday, October 12.
3. HolidaysFederal holidays come from 5 U.S.C. 6103 and the OPM schedule, on the weekday each one is observed.

Is the start date counted?

No. 1 day after Friday is Saturday, and 1 business day after Friday is Monday. This matches how deadlines like “within 10 business days” are usually counted and how spreadsheet WORKDAY functions work.

What if the start date is a weekend?

For business days, counting starts from the next weekday: 1 business day after a Saturday is the following Monday.

Which holidays are skipped?

The 11 federal holidays in 5 U.S.C. 6103, on the weekday each one is observed. State holidays, bank closures and one-time federal closings are not included, so check with the office that sets your deadline.