How to use the days between dates calculator
- Pick a start date and an end date. To count down to an event, press Use today as start and choose the event date as the end.
- Decide whether to include the end date. Leave it unticked to count elapsed days (how most “days until” counts work). Tick it to count every calendar day in the range, for example the number of days in a hotel booking including checkout day, or a 30-day window counted inclusively.
- Press Calculate. If the end date is before the start date, the tool still gives the size of the gap and says so.
Typical uses include counting down to a trip or a wedding, checking how many days are left on a 30-, 60- or 90-day return or notice period, working out someone's age in days, and planning project timelines in weekdays.
How it's calculated
Both dates are converted to calendar days in UTC, so daylight-saving changes can't add or remove an hour and knock the count off by a day.
Weeks = floor(days ÷ 7), remainder = days mod 7
Weekdays are counted by checking every day in the range and skipping Saturdays and Sundays. Public holidays aren't removed, because they differ by country, state and employer. The calendar difference counts whole years, then whole months, then the remaining days, borrowing days from the previous month when needed. That's the same way people say “2 years, 3 months and 5 days”. Leap years are handled automatically.
Worked example
Countdown: from January 1, 2026 to December 25, 2026 is 358 days (51 weeks and 1 day), or 11 months and 24 days. Including Christmas Day itself makes it 359.
Leap year: from February 1, 2024 to March 1, 2024 is 29 days, because 2024 had a February 29.
Work week: from Monday, September 28, 2026 to Monday, October 5, 2026 is 7 days, which contains 5 weekdays.
FAQ
Does the calculator count the start date or the end date?
By default it counts the days elapsed from the start date to the end date, which excludes one of the two endpoints. Tick 'Include the end date' to count both.
How are leap years handled?
Automatically. The tool uses the real calendar, so February has 29 days in leap years such as 2024 and 2028.
Are public holidays excluded from weekdays?
No. The weekday count only removes Saturdays and Sundays. Subtract any public holidays in the range yourself.
How many days are in a year?
365 days in a common year and 366 in a leap year. Over the 400-year Gregorian cycle the average is 365.2425 days.