Date Difference Calculator
Find the exact time between two dates, broken down into years and months, total days, weeks, and working days.
How it works
There are two honest ways to answer 'how long between these dates', and they give different numbers. Counting calendar units gives something like '2 years, 3 months and 4 days'; counting total days gives a single figure. Both are shown, because people mean different things by the question.
Calendar months are not equal, so a month-based answer depends on where you start. From 31 January to 28 February is one month, and so is 1 January to 1 February — one is 28 days, the other 31. The calculation walks the calendar rather than multiplying an average.
Leap years are handled by counting real dates rather than assuming 365 days. That matters for any span crossing a February, and it is where most hand calculations go wrong.
The formula
Total days
count of calendar days from start to end
Weeks
weeks = total days ÷ 7 (with the remainder shown)
Years and months
walk whole years, then whole months, then remaining days
Not total days ÷ 365 — that drifts across leap years.
Worked examples
| Scenario | Working | Result |
|---|---|---|
| 1 Jan 2024 to 1 Mar 2024 | 2024 is a leap year | 60 days, not 59 |
| 15 Mar 2020 to 20 Jun 2023 | Calendar walk | 3 years, 3 months, 5 days |
| A span quoted in weeks | 100 days ÷ 7 | 14 weeks and 2 days |
When you'd use it
- Working out a contract or notice period
- Counting how long until or since an event
- Checking a visa, warranty or subscription length
- Filling in a form that wants a duration in months
Common questions
Why does the years-and-months answer differ from total days ÷ 365?
Because months and years are not fixed lengths. Dividing by 365 ignores leap years and treats every month as equal, which drifts by days over a long span. This tool walks the actual calendar instead.
Does the end date count as a day?
By default no — the difference between the 1st and the 2nd is one day. There is an option to include the end day, which is what payroll and rental periods usually want.
How are leap years handled?
By counting real dates, so 29 February is included whenever it falls inside the span. That is why 1 January to 1 March 2024 is 60 days but the same span in 2023 is 59.