How to Count the Days Between Two Dates

Formula

days = end − start (+ 1 when the end day counts)

full weeks = ⌊days / 7⌋

remaining days = days − 7 × full weeks

business days = days − Saturdays and Sundays

• start and end: the two dates you enter. Each date is a calendar day; the time of day is not used.
• ⌊ ⌋: rounding down
• Saturdays and Sundays: the weekend days among the days counted. Public holidays are not removed.

For years, months and days, full months come off first, then the remaining days are counted. A month is complete when its day is at least the start day.

Step-by-step example

From 14 September 2026 to 14 October 2026:

1. Days: 2026-10-14 − 2026-09-14 = 30 days.
2. Full weeks: ⌊30 / 7⌋ = 4 weeks.
3. Remaining days: 30 − 7 × 4 = 2 days.
4. Business days: the range holds 8 Saturdays and Sundays, so 30 − 8 = 22 business days.
5. Years, months and days: 1 month and 0 days.

If you count the end day too, the result is 31 days, 23 business days and 1 month and 1 day.

Should the end day count?

For a range such as nights at a hotel, the end day does not count. For a period that includes its first and last day, such as how many days an event lasts, it does. The two results for the same year:

A contract or a law can count a period by its own rule; for a deadline, follow the rule of that text.

Months and leap years

Months have different lengths, so the number of days and the number of months do not always match. From 31 January to 1 March:

2024 is a leap year and February has 29 days, so the count is one day higher. Years divisible by 4 are leap years; century years not divisible by 400, such as 1900, are not.

Counting business days

Business days here are Monday to Friday. The public holidays of Law No. 2429, religious holidays and half-day holiday eves are not removed; take the holidays in your range off the result yourself. Where Saturday is a working day, the number of working days is different.