Add or Subtract Days from Date
Add or subtract days, weeks, months, or years from any date.
Written by Anil Gautam · Updated
In what order are years, months and days added?
You can fill all four boxes at once. The calculator moves the year first, then the month, and finally adds the days and weeks together, counting each week as 7 days. Subtract runs the same steps backwards. A negative number typed into any box is reset to 0, so use the Subtract button when you need an earlier date.
The page opens on today's date with 30 already in the Days box. Starting from Wednesday, 7 October 2026, adding 90 days gives Tuesday, 5 January 2027, while adding 3 months gives Thursday, 7 January 2027. Mixed units work too: 1 month and 10 days after 7 October 2026 is Tuesday, 17 November 2026. The start date counts as day zero, so adding 1 day to 7 October returns 8 October.
Why does 31 January plus one month give 3 March?
When the target month is too short for the starting day, the calculator follows the JavaScript date rule and rolls the surplus days into the next month. One month after 31 January 2026 would be 31 February, which is 3 days past 28 February, so the result is Tuesday, 3 March 2026. Subtracting behaves the same way: 31 March 2026 minus one month also lands on 3 March. In the leap year 2028, 31 January plus one month gives 2 March, and 31 May plus one month gives 1 July in any year.
Leap days follow the same rule. Add one year to 29 February 2024 and you get 1 March 2025, because 2025 has no 29 February. Excel's EDATE function stops at the last day of the month and returns 28 February 2026 for the January example, so month-end results can differ between tools by a few days. If you need a month-end date for rent or a bill, add days and check the result: 31 January 2026 plus 28 days is Saturday, 28 February 2026.
Should you add days or months for a deadline?
Use the unit the document uses. Many official time limits and some notice periods are written in days, and a count of days rarely matches the same span in months: 90 days from 7 October 2026 ends two days before 3 months does. If a rule counts the start date as day one, enter one day less than the stated period.
Every calendar day is counted, including weekends and public holidays. To see how many working days fall between the start date and the result, enter both dates in Working Days Between Dates, which skips Saturdays, Sundays and any holidays you list. When you already know both dates and want the gap, Date Difference Calculator gives it in days, weeks and approximate months.