Date Add / Subtract Calculator

Add or subtract days, weeks, months, or years from any date.

Free to useNo signup requiredRuns in your browserUpdated July 2026

Date (Day)

Month

Year

Amount to Add

Unit

Formula / Logic

New Date = Original Date + (Amount × Unit). Supports days, weeks, months, and years.

Day:1

Month:1

Year:2026

Amount:30

Unit:0

Result: Result Date: January 31, 2026, Weekday: Saturday

Can I subtract days by using a negative number?

Yes, enter a negative value in the amount field to subtract days, weeks, months, or years from a date.

Does this account for leap years?

Yes, the JavaScript Date object handles leap years automatically. February 29 is valid in leap years, and February 28 is used in non-leap years.

What happens if I add months to January 31?

Adding 1 month to January 31 gives February 28 (or 29 in leap years), as February 31 does not exist. The date automatically adjusts.