Formula
The inclusive count is the gap plus one:
Inclusive days = end date − start date + 1
The date difference page leaves the start out, so January 1 to January 31 is 30 there and 31 here.
Assumptions
- The end is on or after the start.
- Both dates are calendar dates.
Worked example
January 1, 2026 through January 31, 2026 is 31 days.
Input definitions
- Both dates
- The start and the end each count as one day.
Limitations
This does not skip weekends.
Questions
Why is this one more than the date difference?
Date difference counts the nights between the dates. This page counts both endpoints.
What if the dates match?
The count is 1 day.