MAKE EVERY DAY COUNT
Add or subtract dates
Start with a date. Move forward or back.
Add or subtract from a date
Choose a starting date, then move forward or back.
Choose a date and duration, then select Calculate date.
How to add or subtract time from a date
Choose a starting date, select Add or Subtract, and enter a duration. Mix years, months, weeks and days, or leave any field blank to count it as zero. The result includes the weekday, a calculation summary, and options to copy it or download an all-day calendar event.
Date calculation examples
- January 31, 2026 plus one month is February 28, 2026.
- January 31, 2024 plus one month is February 29, 2024, because 2024 is a leap year.
- March 15, 2026 minus two weeks is March 1, 2026.
- September 25, 2026 plus 10 business days is October 9, 2026 when holidays are included.
What happens when the next month is shorter?
Years and months are applied together first. If the original day does not exist in the target month, the last day of that month is used. Weeks and days are then added or subtracted. For example, January 31, 2026 plus one month and one day becomes March 1, 2026.
Does adding days include weekends?
Calendar time includes every day. Switch Count using to Business days to skip Saturdays and Sundays. You can also exclude nationwide public holidays for a country you select. Regional and employer holidays are not covered.
Is the starting date counted?
A duration moves away from the starting date: one day after September 25 is September 26. Business-day counting also begins after the starting date in the chosen direction. Zero leaves the date unchanged.
Which dates are supported?
Starting and resulting dates must be between 2021 and 2100; excluding holidays works for dates between 2021 and 2035. Business-day offsets support up to 1,000 days. Everything runs on your device, using WherOra’s verified holiday lists for 42 countries.
Already have two dates? Count the business days between them, or return to the calculators overview.