Formula
The new date is the start minus the day count:
New date = start date − days
The add page moves forward. This page only moves backward.
Assumptions
- Days are whole calendar days.
- Weekends are included.
Worked example
January 31, 2026 minus 30 days is 2026-01-01.
Input definitions
- Days to subtract
- A whole number from 0 to 3,660.
Limitations
Time of day and time zones are not included.
Questions
Is January 31 minus 30 days January 1?
Yes, in this example.
Does this count business days?
No. It removes calendar days.