Add Days to Date Calculator
Move a date forward or back by a number of days, weeks, months or years. Use a minus sign to go backward.
- Free
- Works offline after your first visit
- Saves on this device
- No sign-up
- Updated
How it works
Days are counted on the real calendar. A week is seven days, so weeks are multiplied by seven before they are added to the start date.
Months and years keep the same day of the month where that day exists in the new month or year.
Worked example
Starting from 2026-03-15, adding 90 with the unit you chose lands on 2026-06-13, which is 90 days from the start date.
Questions
Does it count leap years?
Yes. It uses the real calendar, so February 29 is counted in leap years.
How do I go back in time?
Type a minus sign before the amount. The new date is then counted backward from the start date.
Why does a month result look odd?
Months have different lengths. A start date late in a month can land on a day that does not match the same number in the new month, so check the date shown.
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