How to use Add or Subtract Days
Use a positive number to move forward and a negative number to move backward. The calculator adjusts across month ends, year ends and leap days, then reports the resulting weekday.
Calendar days include weekends and public holidays. A deadline based on business days or a special legal counting convention needs a separate rule; this tool does not determine those deadlines.
The formula
Resulting date = starting date + signed number of calendar days
A worked example
Starting date: 2026-10-07 · Days to add (negative to subtract): 30
Resulting date: 2026-11-06
Adds calendar days, including weekends and public holidays.
Questions about this calculation
How do I subtract two weeks?
Enter −14 in the days field.
Does this skip public holidays?
No. It counts every calendar day.
Formula checks: 2026-10-08. Assumptions & corrections.