Time & dates
Date Duration Calculator
Count the days between two dates — useful for deadlines, trips, notice periods, and countdowns.
- Enter a start and end date.
- Choose elapsed days or inclusive counting.
- Read the total in days and weeks.
How it works
Pick a start date and an end date. The calculator converts both to calendar days and subtracts them to find the elapsed days — the number of days that pass between the two. It then shows the same total in weeks and days.
Inclusive counting adds one, because it counts both the first and last day on the list. Use it for events, leave, or anything where both end dates are “used”. If the end date is before the start, the result is shown as a positive number and marked as reversed.
Dates are handled as whole calendar days, so the time of day and time zones do not affect the result. Leap years are built in: a period that includes 29 February automatically gains a day. The weeks figure is simply the total days divided by seven, with the leftover days shown separately so you can read it either way. This makes it easy to plan countdowns, track pregnancy weeks, or check how long ago an event took place.
Formula
Elapsed days = End − Start
Inclusive days = End − Start + 1
Worked examples
1 Jan 2024 to 31 Dec 2024: 365 elapsed days, or 366 calendar days counted inclusively (2024 is a leap year).
Hotel stay
Check in 10 June, check out 15 June: 5 elapsed days, which is 5 nights.
Annual leave
Off from Monday 3 August to Friday 14 August: 12 calendar days counted inclusively.
Countdown
From 27 October 2026 to 25 December 2026: 59 days, or 8 weeks and 3 days.
Understanding the result
Elapsed days measure the time that passes (Monday to Tuesday = 1). Inclusive counting counts every calendar day on the list, including both the first and last (Monday to Tuesday = 2). If the end is before the start, the count is shown as a positive number and flagged as reversed.
Common mistakes
- Using inclusive counting for nights, which gives one too many.
- Using elapsed counting for event days, which gives one too few.
- Forgetting that a leap year adds 29 February.
- Counting working days with this tool — it counts all calendar days, including weekends and holidays.
When to use it
- Counting down to a holiday, wedding, or exam.
- Working out notice periods and contract lengths.
- Counting nights for hotels or rentals.
- Checking how long ago something happened.
FAQs
- Which mode should I use for a hotel stay?
- Elapsed — the number of nights is the elapsed days.
- Which mode for an event that runs Mon–Fri?
- Inclusive — it covers 5 calendar days.
- Does it count weekends?
- Yes. Every calendar day is counted. It does not skip weekends or public holidays.
- Can I go back in time?
- Yes. If the end date is earlier, you still get the number of days and a note that the dates are reversed.
- How many days are in a year?
- 365, or 366 in a leap year. The calculator uses the real calendar so you don't need to adjust.
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