Date & time
Days between two dates
Calendar arithmetic is full of traps: leap years, month lengths, and the fact that “one month later” has no single meaning. This tool counts whole days exactly and derives the rest from that.
How to use it
- Pick a start date and an end date.
- Read off the difference in days, weeks, months and years.
- The working-day figure excludes weekends but not public holidays.
- Swap the dates if you want the reverse direction.
Inclusive and exclusive counting
A hotel stay from the 1st to the 3rd is two nights, not three days. A project running from 1 March to 31 March inclusive is 31 days, while the elapsed time between those two dates is 30. Both answers are correct for different questions, and most arguments about “how many days” are really disagreements about which question was asked.
Working days are not just weekdays
Business-day counts depend on jurisdiction: the UK has bank holidays that move with Easter, China creates multi-day blocks by shifting weekend work, and countries with a Friday–Saturday weekend observe a different set entirely. No browser knows any of this, so a weekday count is an upper bound rather than an answer — useful for planning, not for contractual deadlines.
Deadlines, billing periods and the off-by-one
Two dates four days apart contain either four days or five, depending on whether both ends count. Rent, hotel nights and project durations usually count nights, so 1 May to 4 May is three nights, not four. Contracts usually count both ends. Decide which convention the document uses before quoting a number — this single ambiguity causes more billing disputes than any miscalculation.
Working-day counts also need a holiday calendar, which no arithmetic can supply. A span from 20 December to 3 January looks like ten working days and is really two, in most of Europe.
Frequently asked questions
Is the start date counted?
The difference is measured between the two dates as points in time, so 1 January to 1 January is zero days. The working-day count, which describes a span of dates, does include both endpoints.
How are working days calculated?
Weekends are excluded by counting whole weeks and then the remaining weekdays. Public holidays are not known to the browser, so they are not subtracted — the result is an upper bound.
Why does the month count sometimes look off by one?
Whole months only, the same way a person counts. From 31 January to 28 February is zero whole months even though most of a month has passed.
Does daylight saving affect the result?
No. Dates are converted to local midnight and the difference is rounded to whole days, which absorbs the one-hour shift.
How do I count days excluding weekends?
Use working-day mode, then subtract any public holidays — no arithmetic can know a country's holiday calendar.
Does daylight saving affect the result?
Only when counting hours across a transition: one day in spring has 23 hours and one in autumn has 25. Day counts are unaffected.