Days between dates
Enter two dates and the difference is worked out three ways: in days, in weeks, and in calendar parts.
Days
30
Counting both days: 31
- Weeks and days4 weeks and 2 days
- Years, months and days30 days
- Hours720
- WeekdaysSunday → Tuesday
The day count measures the gaps between the dates. To count both the first and the last day, use the line above.
How it works
The number of days counts whole days between the dates. From 1 March to 3 March is two days, because you are counting the gaps rather than the dates themselves.
If both days should count, as for a holiday or a rental period, add one day. That total is shown as well.
The split into years, months and days follows the calendar rather than a fixed number of days per month. It is the same arithmetic as an age: someone born on 29 February has their birthday on 28 February in non-leap years.
Months differ in length, so the split clamps to the last day of the month. From 31 January to 1 March is one month and one day, because 31 February does not exist.
The arithmetic runs in UTC internally, so a daylight saving change can never move a date a day in either direction.
How the difference is worked out
Weeks are the days divided by seven, rounded down, with the remainder shown as days. The split into years, months and days moves the start date forward by as many whole months as fit up to and including the end date and counts the rest in days. Hours are the days multiplied by 24. If the end date is before the start date, the tool counts from the earlier date to the later one and says so. Over longer spans the numbers grow: from 1 January 2000 to 1 October 2026 is 9,770 days, which is 1,395 weeks and 5 days, or 26 years and 9 months.
Example
From Thursday 1 October 2026 to Friday 25 December 2026 is 85 days, or 12 weeks and 1 day. In calendar parts it is 2 months and 24 days: two months on from 1 October is 1 December, and from there it is 24 days to Christmas Day. Counting both days it is 86 days, and the tool shows 2,040 hours.
Edge cases
Around the end of a month, different start dates can give the same calendar difference. From 28, 29, 30 or 31 January 2026 to 1 March 2026 the answer is 1 month and 1 day every time, although the day counts are 32, 31, 30 and 29. That is because one month on from 29, 30 or 31 January is clamped to 28 February.
Hours are always the days times 24, but the real hours between two midnights follow the clock. Under the Summer Time Order 2002, summer time ends at 1am GMT on the last Sunday in October, which in 2026 is 25 October. Between midnight on 1 October and midnight on 1 November 2026 there were therefore 745 hours in the UK, while the tool shows 744.
The tool also uses the Gregorian calendar for every date, including those before Britain adopted it. Under the Calendar (New Style) Act 1750 the day after 2 September 1752 was 14 September, yet the tool counts 12 days between the two dates. For older British records dated in the old style, the difference can be out by eleven days.