Date Calculator
Add or subtract years, months, weeks, and days from any date.
Fill in the fields above to see your result instantly.
This date calculator adds time to — or subtracts time from — a starting date. Choose a start date (it defaults to today), enter how many years, months, weeks, and days to shift by, and pick add or subtract. The result shows the new date and the day of the week it falls on. Month math clamps to the end of the month, so adding one month to January 31 lands on the last day of February, and leap years are handled automatically.
How to use the Date Calculator
- 1
Pick a start date
Defaults to today; change it to any date you like.
- 2
Choose add or subtract
Decide whether to move forward or backward in time.
- 3
Enter the amounts
Type any combination of years, months, weeks, and days. The result updates instantly.
Examples
Frequently asked questions
How does adding months work at the end of a month?
Years and months are applied first, and if the resulting day doesn't exist in the target month, it clamps to that month's last day. For example, January 31 plus one month becomes February 28 (or 29 in a leap year).
Can I subtract time instead of adding?
Yes — switch the Operation to Subtract and the same amounts are removed from the start date.
What order are the units applied in?
Years and months are applied together (with end-of-month clamping), then weeks and days are added as an exact day offset on top.
Does it handle leap years?
Yes. Day offsets cross February 29 correctly, and month math respects each month's real length.