How to use Date Difference Calculator
- Enter the start and end dates (ISO, epoch or "now").
- Choose the calendar timezone and the weekend definition.
- Read the breakdown and totals; copy the ISO duration if you need it in an API.
Date Difference Calculator features
- Calendar breakdown in years, months, days, hours, minutes and seconds
- Totals in days (with decimals), weeks, months, hours, minutes and seconds
- Business days with configurable weekends (Sat–Sun, Fri–Sat, Fri, Sun)
- Inclusive end-day option
- ISO 8601 duration output (P1Y1M14DT8H30M)
- Timezone-aware so day boundaries are correct
Date Difference Calculator example
Project duration
Input:
2024-01-31T09:00:00+03:00 → 2025-03-15T17:30:00+03:00Output:
1 year, 1 month, 15 days, 8 hours, 30 minutes
Total days 409 · Business days 292 · P1Y1M15DT8H30MFrequently asked questions about Date Difference Calculator
How is the calendar breakdown computed?
Years, months and days are counted on the calendar in the selected timezone (31 January → 28 February is 28 days, not one month), then hours, minutes and seconds are added. Totals are exact elapsed time.
What counts as a business day?
Every calendar day after the start date up to and including the end date that is not a weekend. Choose Saturday–Sunday, Friday–Saturday (Gulf region), Friday-only or Sunday-only weekends; public holidays are not excluded.
Why does the timezone matter?
Calendar dates change at midnight local time, so the number of days between two instants can differ by one depending on the zone. Elapsed hours and seconds never change.
What does "Count the end day as a full day" do?
It adds 24 hours to the end date, so a hotel stay from 1 March to 3 March is reported as 3 days instead of 2 (inclusive counting).
Is the ISO 8601 duration exact?
It mirrors the calendar breakdown (P1Y1M14DT8H30M). Because months vary in length it is a description of the difference, not an absolute number of seconds.