Date Add/Subtract — Base Date ± Days
Date & TimeA date add/subtract calculator finds the result date after adding an integer number of days to a base date.
What is it
Date add/subtract is useful for schedules, deadlines, anniversaries, and contract periods. Enter a negative day value to calculate a date before the base date.
result date = base date + days
How to use
- 1Enter the base date.
- 2Enter the number of days to add or subtract.
- 3Press calculate to see the result date and weekday.
Reference
| Base date | Days | Result |
|---|---|---|
| 2026-01-01 | 100 | 2026-04-11 |
| 2026-01-01 | -7 | 2025-12-25 |
Sources & standards
- ECMAScript Language Specification - Ecma International
FAQ
How do I subtract days from a date?
Enter a negative day value. For example, -7 calculates the date 7 days before the base date.
Is date add input sent to a server?
No. This tool runs in your browser and does not send input to a server.