Date arithmetic

Add or subtract from a date

Move any date forward or backward by days, weeks, months or years.

Starting dateOperationAmountUnit

Resulting date

April 1, 2026

2026-04-01

All date calculators

How it works

Add days, weeks, months or years to a date

Add 90 days to a date

Choose the starting date, select Add, enter 90 and use Days to calculate the exact resulting date.

Subtract weeks from a date

Select Subtract and Weeks to move backward in exact seven-day increments.

Calendar-aware months and years

Month and year adjustments preserve a valid calendar day when the destination month is shorter.

Frequently asked questions

Common questions

What date is 90 days from today?

Select today as the starting date, enter 90, choose Days and select Add.

Can I subtract time from a date?

Yes. Select Subtract and choose days, weeks, months or years.

How are months added?

Months follow calendar boundaries. If the destination month is shorter, the result uses its final valid day.