Date Difference Calculator
Count the days between two dates. See the difference in years, months, weeks and days, and the number of business days, with the option to include the end date.
How to use the Date Difference Calculator
- Pick a start date and an end date. The order does not matter, because the result is always a positive number.
- Tick "Include the end date" if both the first and the last day should count, for example for a hotel stay or a leave period.
- Read the number of days, the breakdown in years, months and days, the weeks, hours and the number of business days.
Examples
1 January 2026 to 1 March 2026 is 59 days, which is 8 weeks and 3 days, or exactly 2 months. With the end date included it is 60 days. Of those 59 days, 42 are business days (Monday to Friday).
15 March 2026 to 27 October 2026 is 226 days, or 7 months and 12 days, with 161 business days.
How the days are counted
- Start date counted, end date not: by default the calculator counts the days that pass between the two dates, so the difference between a date and the next day is 1.
- Including the end date: tick the box to count both dates, which adds one day. This is common for stays, leave and ticket validity.
- Years, months and days: complete years come first, then complete months, then the remaining days, using the real length of each month.
- Leap years: 29 February is counted when it falls between the two dates.
- Business days: Saturdays and Sundays are left out. Public holidays are not removed, because they differ by country and region.
When to use a date difference calculator
- Counting the days left until a deadline, trip, exam or event
- Working out contract periods, notice periods and payment terms
- Finding the length of a project in weeks or business days
- Checking how long ago something happened, or how many days old you are with our Age Calculator
Useful date facts
- A week has 7 days, a common year has 365 days and a leap year has 366 days.
- A year is a leap year if it divides by 4, except century years, which must divide by 400. Check any year with the Leap Year Checker.
- Months have 28 to 31 days, so "one month" is not always the same number of days.
Frequently asked questions
How do I calculate the number of days between two dates?
Enter both dates in the calculator. It subtracts the start date from the end date and shows the total number of days, along with the same period in weeks, months and years.
Does the calculator include the end date?
Not by default. The result is the number of days that pass between the two dates. Tick "Include the end date" to count both days, which adds one.
How are business days calculated?
The calculator counts Monday to Friday and skips Saturdays and Sundays. It does not remove public holidays, which vary by country, so subtract those yourself if needed.
Does the order of the dates matter?
No. If the end date is earlier than the start date, the calculator swaps them and shows the difference as a positive number.
Does it handle leap years?
Yes. A leap day, 29 February, is counted whenever it falls between the two dates.
Is my data stored or uploaded?
No. The calculator is free and everything runs in your browser. The dates you enter are never uploaded to a server or stored.