Days between two dates, also as years, months and days, weeks and hours, plus business days after weekends and your own holidays.
By AdminDrafted with AI writing toolsUpdated Checked examples: 6
From Thu 12 Nov 2026 to Wed 10 Feb 2027 is 90 days: 0 years, 2 months, 29 days, or 12 weeks and 6 days. Of those, 64 days are business days.
N counts days from 1 January 1970 in the proleptic Gregorian calendar.
2 whole months from Thu 12 Nov 2026 reach Tue 12 Jan 2027; 29 days more reach Wed 10 Feb 2027.
Months are counted from the start date's day of the month. When that day doesn't exist in a month (the 31st in April, the 29th–31st in February), the month's last day is used.
Weekend: Saturday and Sunday. Holidays that fall on a weekend are not subtracted twice.
Each date is turned into a day number, the count of days since 1 January 1970 in the Gregorian calendar, and the difference of the two numbers is the number of days between them. The years, months and days figure steps whole months forward from the start date; when that day of the month doesn't exist, the month's last day is used. Business days are the total minus weekend days minus any listed holidays that fall on working days.
People use it for notice periods, visa and residence stays, project schedules and interest periods. From 31 January to 1 March 2024 is 30 days, which reads as 1 month and 1 day because one month after 31 January is 29 February in a leap year.
The end date is left out by default, the same convention as subtracting dates in a spreadsheet. Switch on "Include the end date" when both the first and last days count: leave from Monday to Friday is 5 days, not 4.
The days between two dates are the later date minus the earlier one. That count includes the start date and leaves out the end date, as spreadsheet subtraction does: 3 March to 10 March 2026 is 7 days. When both the first and last day count, as for leave from one date to another, add 1 for 8 days.
| Start date | End date | Default day count | Counting both dates |
|---|---|---|---|
| 2026-03-03 | 2026-03-10 | 7 | 8 |
| 2026-03-03 | 2026-03-03 | 0 | 1 |
| 2024-02-28 | 2024-03-01 | 2 | 3 |
| 2026-12-31 | 2027-01-01 | 1 | 2 |
Leap days need no special step: 28 February to 1 March 2024 is 2 days because 29 February falls between them.
The same span also splits into weeks or calendar months: 14 March to 9 August 2026 is 148 days, which is 21 weeks and 1 day, or 4 months and 26 days.
Split the span at month boundaries: count the days left in the start month, add the whole months in between, then add the days into the end month. From 14 March to 9 August 2026:
The total is 17 + 122 + 9 = 148 days. This counts 15 March through 9 August, where subtraction counts 14 March through 8 August; each leaves out one end, so the totals match.
Across a new year, use day-of-year numbers. 20 November is day 324 of 2025, leaving 365 − 324 = 41 days of that year, and 6 February is day 37 of 2026, so 20 November 2025 to 6 February 2026 is 41 + 37 = 78 days.
Find each date's day of the year and subtract. The leap-year columns apply to every year divisible by 4, except century years not divisible by 400, such as 2100.
| Month | Days | 1st is day (common year) | Last day is day (common year) | 1st is day (leap year) | Last day is day (leap year) |
|---|---|---|---|---|---|
| January | 31 | 1 | 31 | 1 | 31 |
| February | 28 (29) | 32 | 59 | 32 | 60 |
| March | 31 | 60 | 90 | 61 | 91 |
| April | 30 | 91 | 120 | 92 | 121 |
| May | 31 | 121 | 151 | 122 | 152 |
| June | 30 | 152 | 181 | 153 | 182 |
| July | 31 | 182 | 212 | 183 | 213 |
| August | 31 | 213 | 243 | 214 | 244 |
| September | 30 | 244 | 273 | 245 | 274 |
| October | 31 | 274 | 304 | 275 | 305 |
| November | 30 | 305 | 334 | 306 | 335 |
| December | 31 | 335 | 365 | 336 | 366 |
For 14 March to 9 August 2026: 9 August is day 213 + 8 = 221, 14 March is day 60 + 13 = 73, and 221 − 73 = 148. The week number and day of the year calculator gives any date's day number directly.
Take 3 to 10 March 2026, Tuesday to Tuesday. Subtracting the dates gives 7. Counting both ends gives 8. Counting neither end gives 6, which is what "clear days" means. Laws and contracts pick one of these, and the wrong one moves a deadline by a day.
| Convention | Start date | End date | 3 to 10 March 2026 | Where it is used |
|---|---|---|---|---|
| Subtraction (calculator default) | Counted | Left out | 7 days | Spreadsheet date subtraction; hotel nights |
| Inclusive | Counted | Counted | 8 days | Leave booked from one date to another; rota counts |
| Clear days | Left out | Left out | 6 days | Notice periods for UK company meetings |
| US federal court deadlines | Left out | Counted | 7 days | Filing periods in days |
UK company law uses clear days. Under the Companies Act 2006, s.360, neither the day notice is given nor the meeting day counts, and s.307 requires at least 14 days' notice of a private company's general meeting.
Notice given on 1 June 2026 therefore allows a meeting on 16 June at the earliest, unless members agree to shorter notice. Subtraction gives 15 days; leaving out 1 June itself leaves 14 clear days.
US federal courts follow Federal Rule of Civil Procedure 6(a): leave out the trigger day, count every day including weekends and holidays, and include the last day. If that day is a Saturday, Sunday or legal holiday, the period runs on to the next day that is not.
A 10-day period triggered on Wednesday 4 March 2026 lands on Saturday 14 March, so it ends on Monday 16 March. To find an end date from a start date and a number of days, use the add or subtract days calculator.
Business days are the total days minus weekend days minus listed holidays that fall on working days. The end-date rule matters here too: April 2026 has 22 weekdays, but counting 1 April to 30 April by subtraction drops Thursday 30 April and gives 21.
England and Wales have two Easter bank holidays in April 2026, Good Friday on 3 April and Easter Monday on 6 April (gov.uk bank holidays). Counting both ends and leaving those out, the month has 20 working days.
Excel's NETWORKDAYS counts both ends: Microsoft's example returns 110 working days from 1 October 2012 to 1 March 2013, while subtraction gives 109 because Friday 1 March 2013 is left out. NumPy's busday_count also leaves out the end date.
A holiday on a weekend is not taken off twice. In England and Wales, 26 December 2026 is a Saturday and the Boxing Day bank holiday moves to Monday 28 December.
From 24 December 2026 to 4 January 2027, listing 25, 26 and 28 December and 1 January removes 3 days, not 4, and leaves 4 business days.
Use the holiday list for the right region: Scotland's 2026 bank holidays include 2 January, 15 June and 30 November but not Easter Monday. To find the date a number of working days after a start date, use the working days deadline calculator.
A month is 28 to 31 days long, so a months-and-days figure depends on where the span starts. Months are counted forward from the start date's day of the month; when that day doesn't exist, the month's last day stands in:
When a contract, loan or statute sets a period in days, use the day count; when it sets months, use the months figure and check the month-end case. The age calculator counts months from the day of birth the same way.
Counting the end date changes the breakdown as well: 1 January to 31 December 2026 is 364 days, or 11 months and 30 days, by subtraction, but 365 days and exactly 1 year when both dates count.
2026-03-03), written out (3 March 2026 or March 3 2026), or today.2026-04-03 Good Friday; none are preloaded.Checked against: Independent calculation
Checked against: Difference = 366 days
Checked against: Independent calculation
Checked against: Independent calculation
Subtract the earlier date from the later one using day numbers, which is what a spreadsheet does with =B1-A1. From 1 January to 31 December 2026 that gives 364 days; add 1 if the last day should count as well, giving 365. Counting on a calendar by months goes wrong at month ends and leap years, which day numbers handle automatically.
It includes the start date and leaves out the end date, so 1 to 3 March is 2 days, matching Excel date subtraction and Python's date arithmetic. Turn on "Include the end date" to count both, which makes 1 to 3 March 3 days. Contracts and statutes sometimes define their own rule, so check the wording when a deadline has legal effect.
2026 has 261 weekdays, Monday to Friday. England and Wales have 8 bank holidays in 2026, all on weekdays (gov.uk lists Boxing Day as Monday 28 December), which leaves 253 working days. For another country, paste its public holidays into the holidays box, one ISO date per line, and they are taken off the business-day count.
Months are counted from the start date's day of the month, and a day that doesn't exist in the target month becomes that month's last day. So 31 January plus one month is 29 February 2024, and 31 January to 1 March 2024 is 1 month and 1 day. Microsoft notes that Excel's DATEDIF with the "MD" unit may return a negative number, a zero or an inaccurate result, which this method avoids.
Divide the number of days by 7: the whole number is the weeks and the remainder is the extra days. 90 days is 12 weeks and 6 days, and a leap year's 366 days is 52 weeks and 2 days. Pregnancy is dated in the same weeks-plus-days form, written 12+6.
This calculator includes 6 worked examples with independently sourced answers. They run in the test suite, and you can run them here too.