Days Between Dates Calculator
Work out how many days, weeks and working days there are between two dates, with or without the end date.
Number of days
278
1 January 2026 · 6 October 2026
Whole weeks
39
Plus extra days
5
Working days (Mon–Fri)
198
Years
0
Plus months
9
Plus days
5
Please note: The result is an estimate and has been rounded. Actual costs and values may differ, and no rights can be derived from this calculation.
How this number is calculated
The blocks use your input. Change a value above and they update with it.
Step 1 · Counts up to
Step 2 · Number of days
Step 3 · Whole weeks
Step 4 · Working days (Mon–Fri)
Step 5 · Whole months
Step 6 · End of the last whole month
Step 7 · Plus days
How the calculation works
Enter a start date and an end date and you see straight away how many days there are between them. You also see how many whole weeks that is, how many working days from Monday to Friday, and how many years, months and days.
The calculator counts the days from the start date to the end date. The start date counts, the end date only when you set ‘Include end date’ to yes: then it counts up to the day after. Weeks are whole weeks of 7 days, plus the days left over. Working days are all Mondays to Fridays in the period; public holidays are not subtracted. For years, months and days it first counts the whole calendar months and then the days left over. Leap years are included automatically.
Formula
Days = end date − start date, plus 1 if the end date is included. Weeks = days ÷ 7, rounded down; the rest are extra days. Working days = 5 × the number of weeks between the weeks of start and end + min(weekday of end, 6) − min(weekday of start, 6), with Monday = 1 and Sunday = 7.
Assumptions
- The start date counts, the end date only if you choose so. Monday to Tuesday is 1 day, Monday up to and including Tuesday is 2 days.
- Working days are Monday to Friday. Public holidays, days off and leave are not subtracted.
- The calculator uses the standard calendar with leap years: 2000 and 2024 are leap years, 2100 is not.
- One month later is the same day of the next month. If that day does not exist, such as 31 April, the 1st of the following month counts.
- Only whole days count, without hours or time zones, for dates from 1900 to 2100.
Example calculations
The button fills in the calculator above, so you can carry on from there.
-
Days until the summer holidays
Number of days
47
Start date 1 June 2026 · End date 18 July 2026 · No
From Monday 1 June to Saturday 18 July 2026.
-
Working days in a project
Number of days
117
Start date 2 March 2026 · End date 26 June 2026 · Yes
From Monday 2 March up to and including Friday 26 June 2026. Subtract any public holidays yourself.
-
Days until Christmas
Number of days
82
Start date 4 October 2026 · End date 25 December 2026 · No
From Sunday 4 October to Christmas Day 2026.
Frequently asked questions
How do I calculate the number of days between two dates?
Subtract the start date from the end date. From 1 October to 5 October is 4 days: the 1st counts, the 5th does not. Across several months you would have to add up the length of each month, which is easy to get wrong. The calculator does it in one go, including leap years.
Should I include the end date?
It depends on what you are counting. For the number of nights in a hotel, leave the end date out. For the length of a holiday, a course or a rental period you usually include it: Monday to Friday is 4 days, Monday up to and including Friday is 5 days. Set ‘Include end date’ to yes for the second.
How many working days are there in 2026?
2026 has 261 days from Monday to Friday. Public holidays such as New Year's Day and Christmas Day have not been subtracted yet. Which holidays you have off depends on your country and your employer.
Does the calculator subtract public holidays?
No. The calculator counts every Monday to Friday, also when it is a public holiday. If a holiday falls on a weekday in your period, such as Easter Monday or Christmas Day, subtract it yourself from the number of working days.
How do I know if a year is a leap year?
A year is a leap year if it is divisible by 4. Century years are only leap years if they are also divisible by 400. That is why 2000 and 2024 were leap years and 2100 is not. A leap year has 366 days, with 29 February as the extra day.
How are months counted when they have different lengths?
One month later is the same day of the next month: 15 March to 15 April is 1 month. If that day does not exist, such as 31 April, the 1st of the following month counts. So 31 January to 1 March is 1 month and 0 days, even though in 2026 there are only 29 days in between.
Sources and checks
Sources
- Holiday entitlement: Entitlement | GOV.UK
- Leap Years | U.S. Naval Observatory, Astronomical Applications Department
How we check it
This calculator has 36 fixed checks: 30 calculations with a result that is fixed in advance, and 6 cases of invalid input that must be rejected. They all run automatically every time we publish; if one fails, the calculator does not go live.
See the calculations
- Start date 1 January 2026 · End date 1 January 2027 · No → Number of days 365
- Start date 1 January 2026 · End date 4 October 2026 · No → Number of days 276
- Start date 1 January 2026 · End date 4 October 2026 · Yes → Number of days 277
- Start date 28 February 2024 · End date 1 March 2024 · No → Number of days 2
- Start date 28 February 2026 · End date 1 March 2026 · No → Number of days 1
- Start date 28 February 2000 · End date 1 March 2000 · No → Number of days 2
- Start date 28 February 2100 · End date 1 March 2100 · No → Number of days 1
- Start date 1 January 2024 · End date 1 January 2025 · No → Number of days 366
- Start date 1 January 2026 · End date 31 December 2026 · Yes → Number of days 365
- Start date 31 December 2025 · End date 1 January 2026 · No → Number of days 1
Changes
- : Sources added and content reviewed.
- : First version.
Last reviewed: · How we build and check our calculators
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