Date Difference Calculator
Calculate the exact difference between two dates in days, weeks, months, and years. Find deadlines, durations, and countdowns instantly.
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How to find the difference between two dates
Pick two dates and see the gap in years, months and days, and as total days, weeks, hours and minutes.
- 01
Pick a start and an end date
Both start at today. The order doesn't matter: if the end is before the start, the tool still shows the gap and marks it as in the past. The swap button flips them.
- 02
Read the breakdown
You get years, months and days, plus total days, weeks, hours and minutes between the two dates.
- 03
Add one if you need to count both ends
The tool counts the days between the dates, the way an elapsed-time calculation does. If your rule counts the first and last day, add 1 to the total.
Counting the end date, or not
From 1 January to 31 March 2026, the tool shows 89 days. That's the number of days you move forward on the calendar, and it's what you want for ages, durations and interest periods. But if you were in a country on both 1 January and 31 March and every day between, you were there on 90 days. Visa rules, hotel nights and leave policies often count that way.
The quick check: if "from Monday to Monday" should be 7, the tool's count is right as it stands. If it should be 8, because both Mondays count, add one. Hotel stays are the in-between case: Monday to Monday is 7 nights, which matches the tool.
Worked examples
Here are a few common questions and what the tool gives, using 2026 dates:
| Question | Dates | Result |
|---|---|---|
| How long since a project started? | 1 Jan 2020 to 31 Oct 2026 | 6 years, 9 months, 30 days (2,495 days) |
| Days left until a deadline | 15 Aug 2026 to 31 Oct 2026 | 77 days, or 11 weeks |
| Length of Q1 2026 | 1 Jan 2026 to 31 Mar 2026 | 89 days elapsed, 90 days counting both ends |
| A year that includes 29 February 2028 | 1 Mar 2027 to 1 Mar 2028 | 1 year, which is 366 days |
Leap years are handled automatically, because the calendar maths uses real month lengths rather than an average. The last row shows the effect: the same "one year" is 365 days for most dates in 2026 to 2027 but 366 days across the end of February 2028.
When people count days
Notice periods and contracts
Check that a 90-day notice period really ends where you think, especially when it crosses months of different lengths.
Counting down to an event
See exactly how many days and weeks remain until a wedding, exam or product launch.
Working out how long ago something happened
Put a past date first and today second to see time elapsed since a purchase, a diagnosis or a last service.
What it doesn't count
- Working days. Weekends and public holidays are counted like any other day; Q1 2026 has 64 weekdays out of 89 days, for example.
- Times of day. Both dates are treated as midnight, so the hours and minutes figures are whole days converted, not clock times.
- Time zones. Dates are read in your device's local time, which is right for most calendar questions.
Months are not all the same length
Because months run from 28 to 31 days, "one month" depends on where you start. 31 January plus one month has no matching day in February, so different systems land on 28 February or 3 March. This tool avoids the problem by counting whole months only when the end day has been reached. That's the same convention most people use when they say "three months ago", and it keeps the years, months and days adding up to the right calendar date.