Date Difference Calculator
How long between two dates, in days, weeks, months and years — with the weekday and weekend split, and an option to count both the start and end dates. Put the dates in either order; they are sorted for you.
Difference between two dates
The off-by-one that catches everyone
There are two honest answers to "how many days between 1 and 5 March": four, if you are measuring the gap, and five, if you are counting the days themselves.
Four is right for a duration — how long something lasts, how many nights in a hotel, how much interest accrues. Five is right when each day counts as a unit — days of annual leave, days of a festival, days billed at a daily rate.
The checkbox picks between them, and the result says which was used. This is the single most common source of a date calculation being one out.
How to use this calculator
- Enter both dates. The order does not matter — if the end is before the start they are swapped and the answer is given as a positive number.
- Tick the box if both dates should count as days.
- Press Calculate for the difference in days, weeks, months, years, and the weekday split.
Weekdays are not business days
The weekday figure counts Monday to Friday only. It does not skip public holidays, because which holidays apply depends entirely on where you are. If you need working days with holidays taken out, use the business days calculator, which handles US federal holidays and England & Wales bank holidays.
Frequently Asked Questions
How do I calculate the exact number of days between two dates?
Enter both dates and press Calculate. By default it gives the gap between them; tick "count both the start and end date" if each day should count as a unit, which adds one.
Why do some calculators give a different answer by one day?
Because there are two valid conventions. The gap between 1 and 5 March is four days; the number of days involved is five. Neither is wrong, they answer different questions. This calculator lets you pick and tells you which it used.
Does this count business days?
It gives a weekday count, Monday to Friday, but does not remove public holidays because those depend on your country. For working days with holidays excluded, use the business days calculator.
Can I put the dates in either order?
Yes. If the end date is earlier than the start date they are swapped automatically and the result is reported as a positive difference, with a note saying so.
How is the months figure calculated?
By counting whole calendar months and then the leftover days, not by dividing by 30. Because months vary in length, the months figure will not equal the days figure divided by any fixed number.