Date Difference Calculator

Count the days between two dates, plus the difference in years, months, weeks and total hours — inclusive or exclusive of the end date.

How the days are counted

The main number is the count of calendar days from the start date to the end date, end date excluded — the same as counting the nights between the two dates. Monday to Friday of the same week is 4 days; two equal dates are 0 days apart. If you need the end date counted as well (a 3-day event from Friday to Sunday, a course of medication, billable rental days), tick "Include end date" and the count grows by one.

Entering the dates in the wrong order is fine: the calculator swaps them for you and notes it under the result, so the duration is always positive.

Worked example

From 19 July 2026 to 19 August 2026 is 31 days — exactly 1 month on the calendar walk, or 4 weeks and 3 days. With "Include end date" ticked it becomes 32 days. Over those 31 counted days (19 July, a Sunday, through 18 August) there are 22 weekdays and 9 weekend days — the weekday count is what the Business Days Calculator would refine further with holidays.

Why years × 365 doesn't match

Long spans cross leap years, and months vary between 28 and 31 days, so the calculator never multiplies — it walks the actual calendar. The years/months/days breakdown counts complete calendar years first, then complete months since that anniversary, then the days left over, exactly like an age is stated on official forms.

Common uses

Frequently asked questions

Is the end date included in the count?
By default, no — the calculator counts the days from the start date up to (but not including) the end date, like counting nights between two calendar dates. Tick "Include end date" to add one day, which is the convention for things like rental days, medication courses or event durations.
Are weekends included?
Yes — the main count is calendar days, so Saturdays and Sundays are included. The result also shows a separate breakdown of weekdays vs weekend days, and our Business Days Calculator counts working days only.
What happens if my end date is before my start date?
Nothing breaks — the calculator quietly swaps the two dates and tells you it did, so you always get a positive duration.
How are months counted when they have different lengths?
The years/months/days breakdown walks the real calendar: full years first, then full months, then the leftover days. That is why 31 January to 1 March is "1 month, 1 day" even though January and February have different lengths.
Do leap years affect the result?
Yes, naturally — the count uses real calendar dates, so 29 February is counted whenever the span crosses one. That is why long spans do not equal years × 365 exactly.

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