Enter values and select Calculate to see your result.
Add or subtract years, months and days from a calendar date
Years and months are applied first, clamping to the last valid day of the destination month, then days are added. Uses calendar dates without timezone shifts.
How to use the Date Calculator
Add or subtract calendar years, months and days from a starting date while handling month ends safely.
- Enter a starting date.
- Choose Add or Subtract and enter units.
- Calculate the resulting date.
Date Calculator formula
Years and months are applied first with invalid days clamped to month end; days are then added or subtracted.
Worked example
Inputs: January 31 plus one month.
What to expect: The result is February 28 in a non-leap year.
How to read your result
Calendar arithmetic does not treat every month as a fixed number of days.
Frequently asked questions
What happens to January 31?
It becomes the last valid day of February for that year.
Does time zone affect it?
No. The tool uses calendar dates rather than time-of-day shifts.