Dates & Time

Add or Subtract a Date

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

How to use this calculator

Enter the requested values, review any options that affect the calculation, and select Calculate. The main answer appears beside the form, with supporting details below it.

How the calculation works

Days and weeks use exact calendar-day steps. Months and years preserve the day number when possible; otherwise the last day of the target month is used.

Example

Six months after January 31, 2026 is July 31, 2026.

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Frequently asked questions

What happens when a target month is shorter?

The calculator uses the final valid day of that month. For example, one month after January 31 is the last day of February.