Date Calculator (Add/Subtract Days)

Add or subtract days from a date to get a new date.

Saturday, March 14, 2026 + 0 days
Saturday, March 14, 2026
Saturday

ISO Date:2026-03-14
Day of Week:Saturday

How to Do It Manually

To add or subtract days from a date manually, count forward or backward on a calendar. For large numbers, convert months to days (using each month's actual day count) to simplify.

  1. Start from your chosen date.
  2. Add or subtract days one month at a time, accounting for each month's length.
  3. Remember that February has 28 days (29 in leap years).
  4. The final date after counting is your result.

Frequently Asked Questions

How do I know if a year is a leap year?

A year is a leap year if it is divisible by 4, except century years (e.g. 1900) which must be divisible by 400 (e.g. 2000 is a leap year).

Can I add months or years instead of days?

This tool specifically adds/subtracts days. To add months, count the days in each month you are crossing.