Date Calculator (Add / Subtract)
Add or subtract days, weeks, months and years from any date.
Result date2026-10-21
Day of weekWednesday
Total shift30 days
How it works
Sometimes you do not want the gap between two dates — you want the date itself. What day will it be 90 days from now? When does a 6-month notice period end? This calculator adds or subtracts any mix of days, weeks, months and years from a start date.
Days and weeks are straightforward arithmetic, but months and years are handled by the calendar. Adding one month to 31 January lands on 28 February (or 29 in a leap year), because February has no 31st — the day is clamped to the end of the month. Example: 15 March 2025 plus 90 days is 13 June 2025, a Friday.
It is useful for deadlines, contract and notice periods, warranty and expiry dates, project planning, and answering the everyday question "what date is X from now?" — and it also tells you which day of the week the result falls on.
Frequently asked questions
How are months and years added?
By the calendar, not by a fixed number of days. Adding a month moves to the same day in the next month; if that day does not exist (like the 31st in a short month), it is clamped to the last day of that month.
Can I combine several units at once?
Yes. Enter any mix — for example 1 year, 2 months and 10 days. Years and months are applied first (by the calendar), then weeks and days are added on top.
Does it show the day of the week?
Yes. Along with the resulting date it tells you which weekday it is, which is handy for scheduling meetings, deliveries or deadlines that should avoid weekends.