Days Between Dates Calculator

This counts the days from one date to another. It sounds like the simplest calculation on the site and it is the one people most often get wrong by a day, because there are two reasonable answers and they differ depending on what you are counting. From 1 January to 3 January is two days if you are counting the gaps between them, which is what a bank counting interest or a courier quoting transit time means. It is three days if you are counting the days themselves, which is what a hotel booking or a leave form means. This calculator gives the gap, the standard interpretation, and also shows the inclusive count so you can see both and pick the one your situation needs. Alongside that it breaks the period into working days and weekend days, which is the figure that actually matters for a project deadline or a notice period, since a fortnight that lands over two weekends is a very different amount of working time from one that does not. Leap years are handled correctly, including the rule that a century year is only a leap year if it divides by 400, which is why 2000 was one and 1900 was not.

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364
days between the two dates
Counting both days365
Weeks52
Working days260
Weekend days104
Approximate months11.96

The headline figure is the gap between the dates. The inclusive count adds one, and is what a booking or a leave form usually means. Working days exclude weekends but not public holidays.

How it works

Both dates are read at midnight, the difference is taken in milliseconds and divided by the number of milliseconds in a day, which is 86,400,000. That gives the gap. The inclusive count adds one to include both end dates. Working days are counted by stepping through the period and skipping Saturdays and Sundays. Weeks are the day count divided by seven and approximate months divide by 30.44, the average month length across a four year cycle. Leap years follow the full rule: divisible by four, except century years, unless they divide by 400.

Worked example

Take the defaults, 1 January 2026 to 31 December 2026. The gap is 364 days, because you are counting from one date to the other rather than counting both. Counting both days inclusively gives 365, which is the length of the year, since 2026 is not a leap year. That is 52 weeks exactly. Stepping through and skipping weekends leaves 260 working days and 104 weekend days, which together account for all 364. Note that public holidays are not removed, so the working figure is calendar working days rather than days actually worked.

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Data sources: leap years follow the Gregorian rule: divisible by four, except century years unless divisible by 400. New Zealand public holidays vary by region and are not deducted here; see Employment New Zealand.

Frequently asked questions

How many days are between two dates?

Subtract the earlier date from the later one. The usual answer is the gap, so 1 January to 3 January is two days. If you need to count both end dates, as a booking or a leave form usually does, add one to get three.

Does this include weekends?

The headline day count includes every day. The working days figure excludes Saturdays and Sundays, and the weekend days figure counts them, so you can see both. Public holidays are not removed, because they vary by region in New Zealand.

How are leap years handled?

Correctly, including the century rule. A year is a leap year if it divides by four, except for century years, which must also divide by 400. That is why 2000 was a leap year and 1900 was not, and it is the rule most manual calculations get wrong.