How to use the date difference calculator
- Pick a start date (today is filled in) and an end date. Use “Swap dates” if you entered them the wrong way round.
- Read the difference as years, months and days, plus the total days, weeks, weekdays, hours and minutes.
- Switch on “Include the end date” when the last day should count as a full day, for example the length of a hotel stay or a leave application.
- Switch on “Include times” to measure between two exact clock times, then copy the summary.
Features
- Difference in years, months and days, total days, and weeks plus days
- Hours, minutes and seconds, using optional start and end times
- Include or exclude the end date with one switch
- Weekday (Mon–Fri) and weekend-day counts for the range
- Weekday names for both dates and automatic handling of reversed dates
- Leap years handled correctly, no uploads, works offline once loaded
How the difference is worked out
The total number of days is the exact count of calendar days between the two dates, so 1 January to 1 March is 59 days in a normal year and 60 in a leap year. Weeks are that total divided by seven, with the remainder shown as days.
The years-months-days breakdown counts whole months from the start date, then the leftover days. Example: 10 May 2000 to 25 August 2024 is 24 years, 3 months and 15 days. If the start day doesn't exist in the end month, reaching the last day of that month counts as a whole month, so 31 January to 28 February is one month.
Include the end date, or not?
By default the end date is excluded, which is how most software counts: from Monday to Wednesday is two days. Include the end date when both ends are “used”: a booking from the 1st to the 3rd occupies three nights only if you count the 3rd, and a leave request from Monday to Wednesday is three days of leave. The weekday count follows the same setting.
Limits
Public holidays are not known to the tool, so the weekday count is business days before removing holidays. Times are treated as plain clock times with no time-zone or daylight-saving adjustment; use the Time Zone Converter if the two moments are in different zones.