Date Difference Calculator
Count the days, weeks, months and working days between any two dates.
- Total days
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- Weeks
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- Working days
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- Weekend days
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This tool runs entirely in your browser. Nothing you enter is uploaded to a server.
Count the time between any two dates — as years, months and days, as a total number of days and weeks, and as working days. You choose whether both end dates count, because that genuinely changes the answer and most tools decide for you silently.
How to use it
- Pick the two datesOrder does not matter; a duration has no direction, and the tool tells you if it swapped them.
- Decide how to countTick the inclusive option to count both the first and last day. Leave it off to count the nights between.
- Read the breakdownCalendar duration, total days, weeks, working days and weekend days, with the convention used shown underneath.
The question behind the question
"How many days between Monday and Friday" has two defensible answers. Four, if you are counting the intervals — the nights in a hotel, the days a payment is late, the gap between two events. Five, if you are counting the days themselves — days worked, days of a conference, days of annual leave used.
Most calculators pick one silently, which is why people so often find that a tool disagrees with their own count and cannot work out who is wrong. This one asks, states which convention it applied, and shows the result both ways if you toggle it.
Calendar duration versus total days
The tool reports both because they answer different questions. Years, months and days is how people describe long spans — a contract of two years and three months, a child of eighteen months. Total days is the precise count, and the one to use for anything arithmetic.
They cannot be converted into each other reliably, because months are not a fixed length. Two spans of exactly 90 days can be three months, or two months and twenty-eight days, depending entirely on which months they happen to cross. Anyone who has tried to reconcile a monthly figure with a daily one has met this.
Working days, and what is deliberately missing
The working-day count is Monday to Friday. Public holidays are not deducted, and that is a choice rather than an omission: holidays differ by country, by region within a country, and often by employer. Applying a single calendar to every visitor would produce confidently wrong answers for most of them.
What the tool gives you is the accurate weekday count, from which subtracting your own holidays is trivial. A future version may accept a holiday list; until then, the honest approach is to be clear about what the number does and does not include.
Why calendar dates rather than timestamps
The most common bug in date arithmetic is subtracting two timestamps and dividing by the number of seconds in a day. It works until a span crosses a daylight-saving change, at which point one day is 23 or 25 hours long and the total comes out fractional — usually rounded into a wrong answer.
This tool never handles a time at all. Dates are treated as plain year, month and day values, so a day is always exactly one day and the clock is irrelevant. Nothing you enter is uploaded or stored.
Frequently asked questions
How many days are between two dates?
That depends on whether you count both ends, which is why this tool asks. From Monday to Friday is four days if you count the gaps — the number of nights — and five if you count the days themselves. Neither is more correct; they answer different questions.
Which should I use?
Count the gaps for things measured in nights: hotel stays, notice periods, interest accrual. Count both ends for things measured in days: days worked, days of a conference, days of leave taken.
How are working days counted?
Monday to Friday, with public holidays not deducted. Holidays vary by country, region and employer, so a tool that silently applied one country's calendar would be misleading. The weekday count gives you the starting figure to subtract your own holidays from.
Does it handle leap years?
Yes, including the century rule — 2000 was a leap year, 1900 was not. Spans crossing 29 February are counted exactly rather than approximated.
Why does the years-and-months figure not match total days divided by 365?
Because months and years are not fixed lengths. Two spans of the same number of days can be different numbers of calendar months depending on which months they cross. The calendar duration answers 'how long in the way people speak'; the total days answers 'exactly how many days'.
Do time zones or daylight saving affect the result?
No. The tool works on calendar dates rather than timestamps, so a clock change can never make a duration come out one day short — which is the most common bug in date calculators.
Is my data sent anywhere?
No. Everything is calculated in your browser.