The working behind the answer
How to use this calculator
Choose a start and end date, then decide which counting convention matches your task. Elapsed counting gives zero for the same date; inclusive counting gives one. Calendar arithmetic handles different month lengths and leap years.
The formula
Days between dates
Elapsed days = end calendar date − start calendar date
Include both start and end dates
Inclusive days = elapsed calendar days + 1
A worked example
From 1 October to 1 November 2026 there are 31 elapsed calendar days: 4 whole weeks and 3 days. Counting both endpoint dates gives 32 days.
Good to know
Weekends and public holidays are included. This tool does not determine contractual deadlines, count business days or convert the span into variable-length calendar months. Dates are treated as calendar values, not local timestamps.
Common questions
Are leap days counted?
Yes. A valid 29 February in a leap year is counted as a normal calendar day.
Why do the two modes differ by one?
Inclusive mode counts both endpoint dates; elapsed mode counts boundaries between them.