Days Between Two Dates
Counting days looks trivial until you must exclude weekends, handle a leap year or decide whether the start day counts. This tool gives three readings of the same gap: calendar days, weeks and working days.
Exclusive or inclusive counting
The difference between two dates is an exclusive count: from January 1st to January 31st, 30 days have elapsed, the start day itself not being counted. For an inclusive count — both boundary days included — add one day; that is the convention for hotel nights.
Inclusive days = elapsed days + 1
Calendar, working and business days
Three notions often conflated. Calendar days count everything. Business days (French "ouvrables") exclude Sundays and public holidays but include Saturdays. Working days (French "ouvres") exclude Saturdays, Sundays and public holidays — the days actually worked in most companies.
| Type | Days counted | Typical use |
|---|---|---|
| Calendar | All, weekends and holidays included | Cooling-off period, notice, statutory limitation |
| Business (Mon–Sat) | Monday to Saturday, holidays excluded | Administrative deadlines, payment terms |
| Working (Mon–Fri) | Monday to Friday, holidays excluded | Production lead times, remote-work quotas |
The working-day count here excludes Saturdays and Sundays but not public holidays, which vary by country and region. Deduct them manually when the count must be exact.
Common use cases
- Resignation notice: counted in calendar days or months, depending on the collective agreement and seniority.
- Cooling-off period: 14 calendar days for distance purchases, from delivery.
- Waiting period: before sick-pay benefits begin, in days, sometimes in business days depending on the scheme.
- Assignment or internship duration: often in working days, with conventions specific to each organisation.
FAQ
Is the start day counted?
No. The gap between two dates is exclusive: it counts the days separating start from end, without the first. Add one day for an inclusive count.
How are working days counted?
Monday to Friday, without deducting public holidays. Holidays vary by country and region — subtract them manually for an exact count.
Why do some years have 366 days?
Leap years include a February 29. A year is leap if divisible by 4, except century years not divisible by 400: 2000 was, 2100 will not be.
How do I count working days without holidays?
Count Monday-to-Friday days, then subtract holidays falling in the interval. Most countries have 8 to 14 public holidays a year, some of which fall on weekends.