Date Difference Calculator
Count the calendar days between two dates, with leap-year accuracy.
How the date difference works
The date difference is the number of calendar days between two dates. Enter a start date and an end date; the calculator returns total days plus weeks and remaining days.
The calculation uses calendar dates, so it handles months of different lengths and leap years correctly — February 28 to March 1 is two days in a leap year and one day otherwise.
This is a calendar-day difference between whole dates. It does not include partial days, times or timezone conversions.
The formula
Days = End date − Start date
Count the calendar days from the start date to the end date. Leap years are handled automatically because the difference is measured in whole 24-hour calendar days.
Worked example
January 1 to February 1
In a non-leap year, January has 31 days, so the difference is 31 days — 4 weeks and 3 days.
Frequently asked questions
How are leap years handled?
The calculator uses real calendar dates, so it counts February 29 in leap years automatically. 2024-02-28 to 2024-03-01 is 2 days; 2023-02-28 to 2023-03-01 is 1 day.
Is this calendar days or business days?
Calendar days. Every day between the two dates counts, including weekends and holidays. There is no business-day mode.
What if I enter the dates in the wrong order?
The end date must not be before the start date. If it is, the calculator asks you to correct the order rather than returning a negative difference.
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