Days Between Two Dates Calculator

Pick a start date and an end date: the calculator instantly shows the number of days between them, in weeks, months and years too, along with the working days in England and Wales.

Start date

End date

Include the end date (+1 day)

From Thursday 8 October 2026 to Friday 25 December 2026 there are 78 days.

In weeks: 11 weeks and 1 day
In months and years: 2 months and 17 days
Working days (England & Wales): 56
Weekend days: 22
Bank holidays on weekdays: 0
In hours: 1,872 hours
In years (average): ≈ 0.21 years

Worked examples

Period	Difference	Both days included
1 January to 31 December 2026	364 days	365 days
8 October to 25 December 2026	78 days	79 days
1 February to 1 March 2028	29 days	30 days
14 July 2026 to 14 July 2027	365 days	366 days
1 January 2000 to 1 January 2026	9,497 days	9,498 days

The third example includes a 29 February: 2028 is a leap year, so February has 29 days.

Common periods in days

Period	Days	Note
1 week	7	Always
1 month	28 to 31	February has 28 days, 29 in a leap year
1 calendar quarter	90 to 92	90 from January to March (91 in a leap year), 91 from April to June, then 92
1 calendar half-year	181 to 184	181 or 182 from January to June, 184 from July to December
1 UK tax year	365 or 366	From 6 April to 5 April; 366 when it includes a 29 February
1 year	365 or 366	366 in a leap year
5 years	1,826 or 1,827	Usually, depending on the number of 29 Februaries
10 years	3,652 or 3,653	Usually, depending on the number of 29 Februaries
100 years	36,524 or 36,525	Only one century year in four is a leap year

Days in each month

Month	Days	Days elapsed at month end (365-day year)
January	31	31
February	28 or 29	59
March	31	90
April	30	120
May	31	151
June	30	181
July	31	212
August	31	243
September	30	273
October	31	304
November	30	334
December	31	365

The old rhyme still works: “Thirty days hath September, April, June and November”; all the other months have 31 days, except February. You can also use your knuckles: make a fist and count the months across them. Each knuckle is a 31-day month and each dip between them a shorter month. After July on the last knuckle, start again on the first, which is why August also has 31 days.

Frequently asked questions

Does the calculation take British Summer Time into account?

No, and that is deliberate. The calculator counts calendar days, not hours: the clocks going forward or back does not change the number of days between two dates. The “In hours” line simply multiplies the days by 24.

How do I convert days into weeks?

Divide by 7: the whole number is the number of full weeks and the remainder is the extra days. 78 days is 11 weeks (77 days) and 1 day.

How are months counted?

A month has passed when you reach the same day number again: from 8 October to 8 December is 2 months. If that day does not exist in the target month (a 31st before a 30-day month, for example), the last day of the month is used. Because months vary in length, “2 months and 17 days” is not always the same number of days.

What is the difference between calendar days, working days and business days?

Calendar days are every day on the calendar. Working days are the days people normally work, usually Monday to Friday excluding bank holidays. “Business days” usually means the same thing, especially for banks and deliveries. The working days calculator explains these terms in detail.

How are the working days in the result counted?

The calculator counts Mondays to Fridays in the period and deducts the bank holidays of England and Wales, including substitute days. Bank holidays that only apply in Scotland or Northern Ireland are not deducted. By default the period runs from the start date (included) to the end date (excluded), exactly like the total number of days.

Is my data stored?

No. The calculation runs in your browser and nothing is sent to the website. Once the page has loaded, the calculator even works offline.

How to use the calculator

Enter the start date. The “Today” button fills in the current date.
Enter the end date. If it is earlier than the start date, the calculation still works: the dates are simply swapped.
Tick “Include the end date” if both days count, for a holiday or a rental, for example.

The result updates with every change. As well as the number of days, you get the difference in weeks, months and years, the working days in England and Wales and the total number of hours. Everything is calculated in your browser: no date is sent over the internet.

How to calculate the number of days between two dates

Counting the days between two dates means counting how many midnights you pass to get from one to the other. From Monday to Tuesday is 1 day; from 1 to 31 January is 30.

By hand, the most reliable way is three steps:

Count the days left in the start month: days in the month minus the start day.
Add the full length of each month in between (31, 30, 28 or 29 days).
Add the day number in the end month.

Example from 8 October to 25 December 2026: there are 23 days left in October (31 − 8), November has 30, and you add the 25 days of December. Result: 23 + 30 + 25 = 78 days.

Should you count the first and the last day?

It depends on what you are measuring. A difference between two dates counts only one of the two days: between checking into a hotel on the 10th and leaving on the 14th there are 4 nights. A duration counts both: a holiday from Monday 10th to Friday 14th lasts 5 days. In that case, tick “Include the end date”, which adds 1.

Number of days = end date − start date (+ 1 if both days count)

Spreadsheets work the same way. With dates in A1 and B1, =B1-A1 gives the difference in days in Excel, Google Sheets and LibreOffice Calc. =DATEDIF(A1,B1,"d") also works, and =NETWORKDAYS(A1,B1) counts the working days, with both dates included (add a range of bank holidays as a third argument to exclude them).

Leap years

A year is a leap year if it is divisible by 4. The exception is century years (divisible by 100), which are only leap years if they are also divisible by 400. So 2000 was a leap year, 1900 was not, and 2100 will not be. 2026 and 2027 have 365 days; the next leap year is 2028.

This is the Gregorian calendar rule. Great Britain and its colonies adopted it in 1752: Wednesday 2 September 1752 was followed by Thursday 14 September. For earlier dates, the calculator extends the Gregorian calendar backwards, which may differ from historical dates recorded in the Julian calendar.