Date Difference Calculator
Days, weeks, months and working days between two dates, counted both ends.
Counting days across months with different lengths is exactly the kind of arithmetic people get wrong by one. This calculator does it properly: pick two dates and get the number of days, weeks, months and years between them, plus how many of those days are working days.
The count includes both the start date and the end date, which is what most people mean by "from the 3rd to the 10th".
At a glance
- What you enter
- Start date, End date
- What you get
- Days between the two dates, Working days (Monday to Friday), Full weeks
- Formula shown
- Yes - every step, right below your results.
- Cost and privacy
- Free, no account needed, and nothing you type is stored.
See worked examples ↓ Read the FAQ ↓ Share this calculator ↓
How is this calculated?
The day count is inclusive of both dates. Weeks are the day count divided by seven, calendar months and years come from the actual difference between the dates, and working days count every day in the range except Saturdays and Sundays.
Public holidays are not subtracted, because they differ by country and year and would make the result depend on a calendar the calculator cannot verify. If you need exact business days for a contract, take the working-day count and subtract the holidays that fall inside the range.
Calendar months: 1
Calendar years: 0
Hours elapsed: 672
What does this mean?
The two dates are less than a month apart. Short ranges are the ones where counting by hand most often lands one day out.
There are 29 between the two dates, counted including both of them. That is 4 full weeks, 1 calendar months and 0 years apart, and 672 hours of elapsed time. Of those days, 21 are working days, which leaves out Saturdays and Sundays but not public holidays.
What should I do next?
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Subtract public holidays from the working-day count if it is for a contract
Working days here exclude weekends only. Public holidays differ by country and year, so they are deliberately not subtracted.
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Remember the count includes both end dates
From the 1st to the 10th is ten days, not nine. If you need the elapsed time instead, subtract one from the day count.
Results are estimates for general information only - always verify with a professional or official source before acting on them.
How to use the Date Difference Calculator
- 1 Enter Start date
- 2 Enter End date
- 3 Press Calculate. You get Days between the two dates, Working days (Monday to Friday), Full weeks, and every intermediate step stays visible under “How is this calculated?”
- 4 Change one number at a time to see what moves the result - that is usually the most useful thing a calculator can tell you.
Worked examples
Real numbers run through this calculator. Open any example to load it into the form above and change it.
A full calendar year, both ends counted
1 January to 31 December 2026.
You enter
- Start date
- 2026-01-01
- End date
- 2026-12-31
You get
- Days between the two dates
- 365
- Working days (Monday to Friday)
- 261
- Full weeks
- 52
A whole year is 365 days because both 1 January and 31 December are counted, and 52 full weeks fit inside it. Of those days, 261 are Monday to Friday and the other 104 are weekend days, with public holidays still counted as working days.
A leap February in full
The whole of February 2028, which is a leap year.
You enter
- Start date
- 2028-02-01
- End date
- 2028-02-29
You get
- Days between the two dates
- 29
- Working days (Monday to Friday)
- 21
- Full weeks
- 4
February 2028 has 29 days, and counting both ends gives 29 rather than 28. There are 21 working days and 4 full weeks in the month, one day more than the same range would give in a year without a leap day.
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Frequently asked questions
Does the day count include the first and the last date?
Yes, both dates are counted. 1 January to 10 January gives 10 days, not 9. That is the reading most people expect from a sentence such as "I am away from the 3rd to the 10th", and it matches the way holiday allowances are usually described.
If you need the number of nights or the full days that elapse between the two dates, subtract one from the result. The full weeks figure is the day count divided by seven and rounded down, so a 10 day range shows 1 full week.
Why are public holidays not taken out of the working days?
Working days here are every Monday to Friday in the range. Public holidays are left in because they depend on the country, the region and the year, and the calculator cannot know which calendar applies to you.
For a contract or a deadline, take the working day count and subtract the holidays that fall inside your range. A two week project that spans a national holiday is one working day shorter, and that is worth writing into the plan before you agree a date.
How are leap years handled?
The calculator counts real calendar days, so 29 February is included whenever it exists. February 2028 has 29 days and a range covering the whole of that month is 29 days inclusive, while the same dates in February 2027 give 28 days.
Leap years matter most over long ranges. A full year is 365 days or 366 days depending on the year, so the same two dates can differ by a day. Over a few weeks the extra day changes the answer only if 29 February falls inside your range.
Can I enter the end date before the start date?
Yes. The two dates are put in order before anything is counted, so 10 January to 1 January gives the same answer as 1 January to 10 January. There is no error and no negative result to interpret.
The result is always a positive number of days, which means the output on its own does not tell you which date came first. When the direction matters, check the two dates before you copy the number into a contract or a booking.
Terms used here
Short, plain-language definitions of the words this calculator uses.