Date Difference Calculator

Count the days between two dates — calendar days or just weekdays — with a weeks-and-days and a rough monthly breakdown. Everything is computed in this browser tab.

Dates

The difference is inclusive: both dates count as part of the span.
Counts only Monday to Friday. Bank holidays depend on your country and are not excluded.
Your dates are remembered in this browser, so a reload keeps them. Clear removes them.

Difference

Pick both dates to see the difference.
-- Calendar days
-- Business days
-- Weeks
-- Months*

Private by design. This page has no backend. The difference is computed by JavaScript on your own device — the dates are never sent anywhere.

How the counts work

Both dates are read as calendar days, local to you, with no clock involved — the time of day never changes the answer. The difference is inclusive, so a project that runs from the 1st to the 3rd works out as three days, which is how booking counts a stay. Every span is counted using the actual lengths of its months, then broken into weeks and whole days; a 12-day span reads as “1 week and 5 days”, not “1.7 weeks”.

Business days

The weekday count runs Monday to Friday and skips Saturdays and Sundays, and each date is counted once even if both fall in the same span. Weekend-only public holidays land on skipped days anyway. Weekday dates that a bank happens to close (a public holiday such as Christmas Day) are counted regardless, because which holidays matter depends on your country — a decision no offline tool can make for you.

Months

The month figure is an average: the total days divided by 30.44, the mean length of a month across a year. Two dates a calendar month apart can report “about 1 month” when they are 28 days nearer or 31 days apart and up; treat it as a rough guide for planning, not a precise unit.

Daylight saving

The dates are normalised to UTC before subtracting, so a spring-forward or fall back in your time zone cannot make a span read as one day too short or long.

Common uses

Counting how long until a deadline or event, checking how long ago something happened, planning a trip or a notice period, quoting a duration in weeks and days, and working out a working-day timeline for a delivery or a sprint.

How to use the Date Difference Calculator

  1. Pick the start and end dates.
  2. Choose whether to count calendar days or business days.
  3. Read the difference in days, weeks and months.

Frequently asked questions

Does it count the end date?

You can choose inclusive or exclusive counting depending on whether the end day should be counted.

Can it exclude weekends?

Yes. Business-day mode skips Saturdays and Sundays.

How is the months figure worked out?

It counts whole calendar months between the dates, with the leftover days shown separately.