Examples
- 90 days after October 29, 2026 is Wednesday, January 27, 2027: 2 days left in October, 30 in November and 31 in December make 63, and 27 more land in January.
- 1 month after January 31, 2026 is February 28. February has no 31st, so the last day of the month is used rather than spilling into March.
- 10 business days after Wednesday, November 18, 2026 is Thursday, December 3, skipping two weekends and Thanksgiving.
How months, weeks and business days are added
Years and months are added first and move along the calendar, keeping the same day of the month (or the last day, if the month is shorter). Weeks and days are then added as exact days. Because months vary in length, “3 months” and “90 days” rarely land on the same date; use days when you need an exact count.
With Business days only ticked, a week counts as 5 working days, and Saturdays, Sundays and U.S. federal holidays are skipped. For UK bank holidays or your own days off, use the business days calculator.
Frequently asked questions
How do I subtract days from a date?
Choose Subtract and enter the days. 45 days before March 15, 2027 is January 29, 2027.
Is adding 6 months the same as adding 182 days?
No. Six months lands on the same day of the month six months later; 182 days is a fixed count and can be a day or two off from that.
How do I add days to a date in Excel?
Use =A1+90 for days and =EDATE(A1,6) for months. For working days, =WORKDAY(A1,10), with a list of holidays as the third argument if needed.