Date Difference Calculator
How long between two dates — in days, weeks, months, and years.
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Enter two valid dates to see the difference.
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How to use it
Enter two dates to see how far apart they are in days, weeks, months, and years — with a switch for whether to count the end date.
Enter a start and end date and the gap appears in every unit at once: days, weeks, months, and years, plus how many are weekdays and how many are weekend days.
Should the last day count? It depends. A hotel stay from the 3rd to the 6th is three nights, but a conference from the 3rd to the 6th is four days. Use the switch to pick — the label tells you which answer you’re seeing.
Leap years are handled automatically.
Need working days only? Use Business Days. Wondering what weekday a date falls on? Look it up here.
FAQ
How many days are between two dates?
Enter both dates and the count appears straight away. Tick “count the end date as a full day” to include both ends.
Why do I get two answers with the switch?
Both are right for different questions: “how many nights” versus “how many days does it run”. They always differ by one.
Does it count leap years?
Yes. 29 February is included whenever it falls in the range.
How are months counted?
As whole months between the dates, with any leftover shown in days.
Are hours and minutes exact?
They assume every day is 24 hours, so they can be an hour out if the clocks change in that time.
How it worksFor the curious
Both dates are converted to a fixed day number and subtracted, rather than measuring elapsed hours. Across a daylight saving change a day is 23 or 25 hours, so elapsed-time maths drifts by a day about twice a year. The hour and minute figures are conversions of the day count and assume 24-hour days.
The years-months-days breakdown finds the largest whole number of months that fits inside the span, then measures the remainder in exact days. Naive borrowing fails at month ends (31 January to 1 March); this approach is reversible — adding the breakdown to the start date always returns the end date. It is the same breakdown the age calculator reports.