How to calculate days between two dates
Months have different lengths and leap years add a day. Here is how to count days, weeks and working days between any two dates correctly.
Counting the days between two dates sounds simple, but months have different lengths, leap years add a day, and people disagree about whether to count the first and last day. Here is how to do it correctly, with examples.
Exclusive vs inclusive counting
Most calculators, including ours, count the difference between two dates. From Monday to Friday of the same week is 4 days. This is "exclusive" counting: you count the nights in between, as a hotel does.
For leave applications, rental periods or event durations, people often count both the start and end day. Monday to Friday is then 5 days. To switch from exclusive to inclusive, simply add 1.
Method 1: Count by months
- Count the remaining days in the start month.
- Add the full days of each month in between.
- Add the day number of the end date.
Example: 1 January 2026 to 14 August 2026. January has 30 days left after the 1st, then February 28, March 31, April 30, May 31, June 30, July 31, then 14 days of August: 30 + 28 + 31 + 30 + 31 + 30 + 31 + 14 = 225 days. Counting both dates, it is 226 days.
In years, months and days the same period is 0 years, 7 months and 13 days.
Days in each month
| Month | Days | Month | Days |
|---|---|---|---|
| January | 31 | July | 31 |
| February | 28 (29 in a leap year) | August | 31 |
| March | 31 | September | 30 |
| April | 30 | October | 31 |
| May | 31 | November | 30 |
| June | 30 | December | 31 |
Leap years
A year is a leap year if it divides by 4, except century years, which must divide by 400. So 2024 and 2028 are leap years, 2026 is not, 2000 was, and 2100 will not be. A period that includes 29 February of a leap year has one extra day.
Working days
Working days exclude weekends. From 1 January 2026 to 14 August 2026 (counting both dates), there are 162 working days with a Saturday–Sunday weekend, as in Pakistan, the UK and the US. With a Friday–Saturday weekend, as in Saudi Arabia, there are 161.
Public holidays are extra: subtract any that fall on a weekday. In Pakistan, Eid and other Islamic holidays move each year with the lunar calendar, so check the official holiday list for the year.
Quick estimate: in a full week there are 5 working days, so 52 weeks have about 260 working days before holidays.
Weeks and months
- Weeks: divide days by 7. 225 days is 32 weeks and 1 days.
- Months: count calendar months first, then the leftover days, rather than dividing by 30, since months are not all 30 days.
Common uses
- Notice periods and leave applications.
- Days until an exam, a wedding or a deadline. From 6 October 2026 to 31 December 2026 is 86 days.
- Loan or rent periods, and interest that is charged per day.
- Pregnancy and visa durations, where official bodies may count in their own way, so follow their rules.
Skip the counting with the date difference calculator, which shows days, weeks, months and working days with your choice of weekend.
Frequently asked questions
How do I calculate the number of days between two dates?
Count the remaining days in the first month, add the days of each full month in between, then add the day number of the end date. Add 1 if you want to include both dates.
Should I include the start and end date?
A standard difference excludes one end (Monday to Friday is 4 days). For leave or bookings that count both days, add 1.
How many working days are in a year?
About 260 with a Saturday–Sunday weekend, before subtracting public holidays.
Is 2026 a leap year?
No. 2026 has 365 days. The next leap year is 2028.
How many weeks are between two dates?
Divide the number of days by 7. The remainder is the extra days.