Date Difference Calculator
Calculate the exact number of days, weeks, months and years between any two dates, with business-day and weekend breakdowns.
Written by Rahman · Last reviewed
Quick answer
The gap between two dates is a count of days, which can then be expressed in weeks, months or years. Day counts are exact; month and year figures are approximations, because month arithmetic is genuinely ambiguous: the interval from 31 January to 28 February is not a clean month by any consistent definition.
| Business days (Monday to Friday) | 734 |
| Saturdays | 146 |
| Sundays | 146 |
The range counts the start date and stops before the end date, which is how notice periods and delivery windows are normally counted. Public holidays are not deducted — they vary by country and by year, so business days here means weekdays.
Results are estimates for general guidance only. Double-check any figure you rely on for an important decision.
About the Date Difference Calculator
Finding the gap between two dates is useful for project planning, counting down to events, tracking deadlines and measuring durations.
This calculator gives the difference between a start and end date as a total number of days, and also as a breakdown of years, months and days.
Whether to count both ends changes the answer
"How many days between two dates" has two defensible answers, and the difference is always exactly one. Counting the elapsed days between them (the exclusive count) treats the span as a duration. Counting every day from the first to the last inclusive treats it as a set of days.
From 1 January to 31 January is 30 days elapsed and 31 days inclusive. This calculator reports the elapsed count, which is the convention for durations, ages and intervals. Where the answer matters, say which you mean rather than assuming the reader shares your convention.
- Notice periods, rental agreements and legal deadlines frequently specify inclusive counting, and being one day out can be consequential.
- Hotel and hire bookings count nights, which is the exclusive figure: a Friday to Sunday stay is two nights, not three days.
- Payroll and interest calculations vary: some conventions count the start date, others the end, and some use fixed 30-day months regardless of the calendar.
Months and years are not fixed lengths
A total in days is unambiguous. Breaking that total into years, months and days is not, because months vary between 28 and 31 days and years between 365 and 366. The same span can be described several ways depending on the order of operations.
Leap years follow a rule with two exceptions: every year divisible by 4 is a leap year, except centuries, except those divisible by 400. So 2024 and 2000 were leap years and 1900 was not, a distinction that still causes bugs in date arithmetic.
- Adding one month to 31 January has no obvious answer, and different systems return 28 February, 2 March or 3 March.
- Spans crossing a daylight saving transition contain a day of 23 or 25 hours, which matters when the answer is needed in hours rather than days.
- For anything contractual, count in days. The day count is the figure that cannot be interpreted two ways.
Frequently Asked Questions
Does it include both the start and end date?
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It counts the elapsed time between the two dates. To include both endpoints as full days, add one to the total days.
Are leap years handled?
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Yes. The calculation uses actual calendar dates, so leap years and different month lengths are accounted for.
Does the order of the dates matter?
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No. The calculator uses the absolute difference, so it works whether the start date is before or after the end date.
Why are there two different results?
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Total days is a single elapsed count, while the years-months-days breakdown reflects the uneven lengths of calendar months.