Date Difference Calculator

Need to work out how much time has passed between two dates, or how far apart they are? This tool calculates the exact difference between a start date and an end date, showing the result in years, months, and days, as well as the total number of days and weeks. It's useful for calculating ages, measuring the time between events, tracking project durations, or working out how long until an important milestone.

Simply select your start and end dates to get your results instantly. All calculations are performed directly in your browser, with nothing sent to a server, keeping your date information private.

Date Difference Calculator

Start date

End date

Count both the start and end date (inclusive)

Calculated locally in your browser the moment you pick both dates.

How to use it

The date difference calculator works out exactly how much time sits between two dates.

Pick a start dateUse the date picker or type a date directly.
Pick an end dateIt can be before or after the start date — the result is shown either way.
Inclusive counting (optional)Tick the box if you want both the start and end date counted, such as for booking a venue "from the 1st to the 5th".
Read the resultYou'll see a years/months/days breakdown plus total days, weeks and months.

Good to know

Nothing is uploaded

Dates are compared entirely in your browser.

Order doesn't matter

Enter the dates in either order — the calculator works out the difference either way.

Inclusive vs exclusive

By default the end date isn't counted (1 Jan to 3 Jan is 2 days). Tick 'inclusive' to count both ends (1 Jan to 3 Jan becomes 3 days).

Frequently asked questions

How many days are between two dates?

Pick your two dates and the total days figure updates automatically, accounting for leap years.

Why does the total change when I tick 'inclusive'?

By default the calculator measures the gap between the two dates (exclusive of the end date). Ticking 'inclusive' adds one day so both the start and end date are counted — useful for things like counting the nights or days of a booking.

Does it account for leap years?

Yes, the calculation is based on real calendar dates, so leap years are handled automatically.

Can I use this to calculate age?

Yes — set the start date to a date of birth and the end date to today for an exact age in years, months and days.