Formula
days = end date − start date (+ 1 if both ends are counted)
- Dates are converted to day numbers on the calendar, so month and year lengths are exact.
Count how many calendar days lie between the two dates.
Worked example
Across a leap year
- Start date
- 2024-01-01
- End date
- 2025-01-01
- Count the end date?
- No — count the nights between (default)
Days between
366 days
Weeks and days: 52 weeks, 2 days
Years, months, days: 1 year
Weekdays (Mon–Fri) in the range: 262
How it works
From 1 January 2024 to 1 January 2025 is 366 days because 2024 is a leap year. Normally you do not count the start date itself: 1 January to 2 January is 1 day. Choose “include the end date” when both days count, for example a hotel stay is nights but a conference is days.
The calendar breakdown (years, months, days) uses whole months, so 31 January to 1 March in a leap year is 1 month and 1 day. The result also shows weekdays (Monday–Friday) in the range; for a precise working-day count that handles holidays use the Working Days Calculator.
To count forward or back from a date use Date Calculator: Add or Subtract Time; for time until a future date see Days Until Calculator.
Assumptions and limits
- If the end date is before the start date the two are swapped and a note says so.
- Dates only — clock times and time zones are not involved.