Date Difference Calculator
How many days between two dates? Get the total days, weeks, a calendar breakdown and the working days — for deadlines, projects, rentals and countdowns.
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End date not included in the count. Public holidays are not subtracted from working days.
How the date difference is calculated
The calculator works on real calendar dates, so leap years and different month lengths are handled exactly. It shows the same duration in the units people actually need: total days for countdowns, working days for deadlines, and a years-months-days breakdown for durations like contract lengths.
Pick two dates
Past or future — reversed dates are swapped automatically. "Start = today" sets up a countdown.
Read the duration
Total days as the headline, plus weeks, the calendar breakdown and working days below.
Mind the convention
The end date is not included. For "both days count" cases like rentals, add 1.
Off-by-one: the classic date mistake
Is March 1 to March 4 three days or four? Both — depending on the convention. The difference between the dates is 3 days (this calculator's answer, matching spreadsheets and programming languages). But if both end dates count, as with hotel nights billed per day or medication schedules, it's 4. Knowing which convention a form or contract uses matters more than the arithmetic — and it's the number one source of deadline errors. The working-days figure counts Mondays through Fridays in the range; subtract your local public holidays for a precise business-day deadline.
Frequently asked questions
How are the days between two dates counted?
The calculator counts the difference between the two calendar dates: from March 1 to March 4 is 3 days. If you need both end dates included — common for rental periods — add 1 to the result.
What counts as a working day?
Monday through Friday. Public holidays vary by country and region, so they are not subtracted — for precise deadline math, subtract your local holidays from the working-day count.
Are leap years taken into account?
Yes. The calculation uses real calendar dates, so February 29 and months of different lengths are handled automatically.
Can I calculate a duration into the future?
Yes — set the end date to any future date to count down to a deadline, event or vacation. If the dates are reversed, the calculator swaps them automatically.