Using the Day Counter
The calculation subtracts the start date from the end date. Two identical dates give zero; consecutive dates give one. If you need an inclusive count that treats both endpoints as occupied days, add one to a nonnegative difference after deciding that this convention fits your task.
Worked example
Use the example inputs below to reproduce this result. These are the form's starting values, not recommended targets. Changing your inputs updates your result above; this worked example stays fixed for comparison. Results are rounded for display.
Example inputs
- Start date
- 2026-01-01
- End date
- 2026-12-31
Example result
- Calendar days (end minus start)
- 364
- Start weekday
- Thursday
- End weekday
- Thursday
Method and assumptions
Uses calendar dates in UTC to avoid daylight-saving offsets. The end date is not counted as an additional day.
Separate calendar dates from moments in time
A calendar date names a day, while a timestamp identifies a moment that can fall on different dates in different places. Decide which one your task uses before comparing results. Date differences also depend on whether endpoints are counted inclusively. State the convention alongside the answer when someone else needs to reproduce it.
Common question
Why is January 1 to January 2 only one day?
One day elapses between the dates. Counting both named dates as items would give two, but that is a different convention. This tool reports elapsed calendar days and does not add an extra day for the end date.
Guide updated .