Practical guide 3 min read
How to count business days between two dates
Count working days with the right weekends, public holidays and days off, and avoid the classic off-by-one mistake.
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Add or Subtract Dates
Move a date forward or backward by years, months, weeks, calendar days or business days.
Your time, clearly
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Choose your options to begin.
Excluded holidays and custom dates
How this calculation works
Adding one month to January 31 lands on the last day of February. A business-day offset skips days outside your workweek and your excluded dates. Calendar weeks always add seven days.
Worked examples
- 90 days after March 1, 2026 is Saturday, May 30, 2026.
- One month after January 31, 2026 is February 28, 2026 (February 29 in a leap year such as 2024): adding a month to a day the next month doesn't have lands on its last day.
- 10 business days after Friday, December 18, 2026 is Tuesday, January 5, 2027 with US federal holidays, which skip Christmas Day and New Year's Day. With Ontario holidays it's Wednesday, January 6, because Boxing Day is observed on December 28.
Questions
Is the start date counted?
No. Adding 1 day to a Monday gives Tuesday, and adding 1 business day to a Friday gives the next working day, usually Monday.
In what order are years, months, weeks and days added?
Years and months first, then weeks as 7 calendar days, then the days as calendar or business days. So 1 month and 1 day after January 31, 2026 is March 1: February 28, then one more day.
How do I count back from a deadline?
Choose “Subtract / move backward” as the direction, for example to find the date 30 business days before a closing date.
Part of Date Calculator
Calculate date differences, business days, age, date offsets and work hours with custom workweeks, holiday calendars and CSV exports.
A little guidance