Date Calculator

Quickly add or subtract years, months, weeks and days from a date. The calculator uses calendar-aware arithmetic, so month rollovers (e.g., Jan 31 → Feb 28/29) are handled correctly.

How it works

Adding or subtracting years and months uses calendar arithmetic: months and years are changed on the calendar, then weeks/days are added/subtracted. For example, adding 1 month to January 31st results in February 28th (or 29th in leap years).

Example

Base date: 2024-01-31. Operation: Add 1 month → Result: 2024-02-29 (leap year behaviour).

Input rules

  • Base Date must be a valid date input.
  • All numeric fields must be non-negative integers.
  • The operation applies in calendar order: years → months → weeks → days.

Frequently Asked Questions

If the target month lacks the day (e.g., adding 1 month to Jan 31), the calculator uses the last valid day of that month.
Yes — leap years affect February length and are handled automatically.
Yes — choose 'Subtract' and provide the same fields (years, months, weeks, days) to subtract from the base date.