Date Difference Calculator — Days Between Dates

How to use Date Difference Calculator — Days Between Dates

1Pick the two dates you want to compare.
2Adjust the options if you need to.
3Read the result — it updates immediately, and nothing is sent anywhere.

About Date Difference Calculator

Counting days by hand is one of those tasks that looks trivial until the span crosses a month boundary. February has 28 days, or 29 in a leap year; July and August both have 31; and "three months" can be 89, 90, 91 or 92 days depending on where in the year you start. This calculator sidesteps all of that by working with real calendar dates and reporting several answers at once: the plain day count, the day count expressed as weeks plus leftover days, the number of whole months, and the years-months-days breakdown that contracts and visa forms usually ask for.

The working-days figure is the one most people arrive for. It counts every Monday to Friday between your two dates, both ends included, which matches how a project plan or a payroll period is normally read. It stops short of deducting public holidays, and that is on purpose: a holiday calendar that is right for India is wrong for Ireland, and a tool that quietly assumed one would produce confidently incorrect numbers. The weekend-day count is shown alongside it so you can check the arithmetic yourself, then subtract whichever holidays apply to you.

Two details prevent the off-by-one errors that plague date arithmetic. First, all dates are treated as UTC midnight, so a span that crosses a clock change is not silently 23 or 25 hours long in one place. Second, the inclusive-versus-exclusive question is exposed as a checkbox rather than guessed at — because "days between" and "how many days is this booking" are different questions, and the difference is exactly one day in every case that matters.

Frequently asked questions

Is the last day counted, or not?

By default it is not: 1 January to 2 January is 1 day, which is what "days between" normally means. Tick "Count both the start and the end date" and the same pair becomes 2 days — that is the count you want for notice periods, hotel-style day counts and anything where the first day is day one.

Why isn't the years and months breakdown just days divided by 365?

Because months are 28 to 31 days long and every fourth year has an extra one. This tool walks whole calendar months from the start date and then counts the leftover days, which is what people mean by "2 years and 3 months". Dividing total days by 365 gives a visibly different answer across any span containing a leap year.

How are the working days counted?

Every Monday to Friday from the start date to the end date, with both dates included. For 1 September 2025 to 30 September 2025 that is 22 working days out of 30 calendar days, because eight of them are Saturdays and Sundays.

Does it deduct public holidays?

No, and that is a deliberate limitation rather than an oversight — bank holidays, national days and religious holidays differ by country, state and employer, so any built-in list would be wrong for most visitors. Subtract your own holidays from the working-days figure.

Does it handle leap years correctly?

Yes. It uses real calendar dates, so 29 February is included whenever it falls inside your span, and the tool tells you how many 29 Februaries that was. A year is a leap year when it divides by 4, except century years, which must divide by 400 — so 2000 was a leap year and 1900 was not.

What dates can I enter?

Any four-digit year in yyyy-mm-dd form, which is what the date picker produces. Impossible dates such as 30 February are rejected rather than silently rolled forward into March, and the calculation runs entirely in your browser — nothing you type is uploaded.