Calculator
Add or Subtract Days
Start from any date, then add or subtract days, weeks, months, or years to find the resulting date.
How to add or subtract from a date
Pick a start date, choose whether to add or subtract, enter an amount, and select the unit. The tool instantly shows the resulting date, including the day of the week. It handles month lengths and leap years automatically.
Frequently asked questions
What happens with months of different lengths?
Adding months moves to the same day number in the target month where possible. If that day doesn't exist (e.g. January 31 + 1 month), it rolls to the nearest valid date, matching how calendars normally behave.
Can I count backward?
Yes — choose Subtract to find a date in the past, such as "90 days before" a deadline.
Is it free?
Yes, completely free and no sign-up required.