Date Difference Calculator
Count the days between two dates, and see the difference in weeks, months, years, weekdays and hours. Handles leap years and month ends correctly.
- Days
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- Weeks
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- Months
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- Weekdays
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- Weekend days
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- Hours
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How to use the date difference calculator
- Choose a Start date and an End date. The Today button sets the start date to the current date, so you can count the days until a deadline.
- Tick Include the end date (add 1 day) if both the first and the last day should be counted, for example for a hotel stay counted in days or a leave request.
- Read the result in Years, months and days, and the totals in Days, Weeks, Months, Weekdays, Weekend days and Hours.
- Use Swap dates to exchange the two dates. If the end date comes before the start date, the tool says so and shows the gap as a positive value.
How the difference is counted
By default, this tool counts the number of days you need to add to the start date to reach the end date, as most calendars and programming languages do. From January 1 to January 2 is one day; from January 1 to December 31, 2026 is 364 days. With Include the end date (add 1 day) ticked, the same period counts 365 days, because both January 1 and December 31 are included.
The years, months and days result follows the calendar: the tool counts the whole months from the start date, then the days left over. From March 15 to June 20 is 3 months and 5 days. When the start day doesn’t exist in the target month, the last day of that month is used: from January 31 to February 28, 2025 is exactly one month.
The calculation uses calendar dates only. Daylight saving time changes, which make some days 23 or 25 hours long, never add or remove a day. The Hours figure is simply the number of days × 24.
Leap years, weeks and weekdays
Leap years are handled automatically: February has 29 days in years divisible by 4, except century years not divisible by 400. So 2000 and 2024 were leap years, but 1900 was not and 2100 will not be. From February 28 to March 1 is 2 days in 2024 and 1 day in 2025.
The Weeks result shows whole weeks plus the remaining days. Weekdays counts every day of the period that is not a weekend day, and Weekend days counts the others. The Weekend setting chooses the weekend: Saturday – Sunday by default, or for example Friday – Saturday as in most Arab countries. For example, from September 1 to October 1, 2026 there are 30 days: 22 weekdays and 8 weekend days. Public holidays differ from country to country and are not subtracted, so remove them yourself to get the number of working days.
Common uses
- Counting the days until an exam, a trip, a wedding or a due date.
- Checking a notice period, a trial period or a warranty.
- Working out the length of a contract, a rental or a project in months and days.
- Finding how many working days a task can take between two dates.
Frequently asked questions
How many days are there between two dates?
Enter both dates: the Days figure is the number of days from the start date to the end date, not counting the start day. Tick Include the end date (add 1 day) to count both ends.
Should I include the end date?
It depends on what you are counting. For a duration or a deadline (“in how many days?”), leave it unticked. For a period where every day counts, such as days off, days of a festival or nights plus the departure day, tick it.
Does this tool count working days?
It counts weekdays: Monday to Friday by default, or the days you set with the Weekend option (for example Friday–Saturday). It doesn’t know public holidays, which vary by country and region, so subtract those that fall within the period.
Why is "1 month" not always 30 days?
Because months have 28 to 31 days. A month from January 15 is February 15 (31 days later), while a month from February 15 is March 15 (28 or 29 days later). The Months result follows the calendar, and Days gives the exact count.
Are my dates sent to a server?
No. Everything is calculated in your browser, and nothing you enter leaves your device.
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