Add or subtract days, weeks, months or years from a date and get the resulting date.
Enter the date and span
Pick the start date, add or subtract, and set the value in days, weeks, months or years.
Precise calendar calculations. Everything is computed instantly in your browser, no account, no data sent. Leap years and Gregorian calendar rules are handled.
Pick a start date, an operation (add or subtract) and a span in days, weeks, months or years. The result respects real month lengths and leap years:
1 January 2026 + 30 days = 31 January 2026. 31 January + 1 month = 28 February (last valid day).
Pick the start date, tap “Add” and enter the number of days. For example, 1 January 2026 + 30 days = 31 January 2026.
Tap “Subtract” and enter the number of days. 1 March 2026 − 10 days = 19 February 2026 (leap years are handled).
Choose the “weeks” unit; 7 days are added per week. 5 weeks = 35 days, so 1 January + 5 weeks = 5 February.
Choose the “months” unit. 31 January + 1 month gives 28 (or 29) February, because the next month has fewer days — the last valid day is used.
Choose the “years” unit. 29 February 2024 + 1 year = 28 February 2025, since 2025 is not a leap year.
The calculator shows the weekday (Monday, Tuesday, etc.) of the resulting date and the total difference in days from the start date.
Apply each unit in turn: years first, then months, then days, using the intermediate result as the new start date.
Payment terms (invoice + 30 days), due dates, expiry dates, warranties, notice periods and planning.