Date Add / Subtract
Add or subtract years, months, weeks and days.
Monday, October 5, 2026 (2026-10-05)
โ Added 30 days from 2026-09-05. Day of week: Monday.
About the Date Add / Subtract
Offset any date by years, months, weeks and days in one step, in either direction. The result shows the full long-form date including the weekday, plus a note of exactly how many days were added or subtracted. Useful for deadline math, warranty expiry, subscription renewals and pregnancy or milestone dating.
How to use the Date Add / Subtract
- Pick the start date, or press Use today.
- Choose Add time or Subtract time from the dropdown.
- Fill in any combination of years, months, weeks and days.
- Read the resulting date with its day of week in the Result box.
Date Add / Subtract FAQ
Can I mix units in one operation?
Yes โ years, months, weeks and days are all applied together in that order, so adding 1 month and 15 days to January 31 lands where the calendar rules place it.
What happens at month ends?
Month arithmetic follows JavaScript date rules: adding one month to January 31 yields March 3, because February has no 31st โ check the resulting weekday line to confirm the outcome.
Why is the day of week shown?
Most deadline and scheduling decisions depend on whether the target lands on a weekend, so the weekday is surfaced in both the result and the summary note.