Counting days between two dates
This calculator counts the calendar days from a start date to an end date, and converts them to weeks, months, years, hours and business days. You can choose whether the end date counts too, which changes the result by one day.
Include the end date or not?
- Not included (the default): the result is a duration, like the time until a deadline or between two events. From Monday to Friday is 4 days.
- Included: both dates count, as for a vacation, a hotel booking priced per day, a rental or a sick leave. From Monday to Friday is 5 days.
The formulas
- Days = end date − start date (+ 1 if the end date is included)
- Weeks = days ÷ 7, with the remainder in days
- Months ≈ days ÷ 30.44, the average length of a month
- Years ≈ days ÷ 365.2425
- Business days: Mondays to Fridays in the period, counted week by week
Worked example
From November 3, 2026 to February 1, 2027, end date excluded:
- November 3 to December 1: 28 days.
- December 1 to January 1: 31 days; January 1 to February 1: 31 days.
- Total: 90 days, or 12 weeks and 6 days.
- Business days: 12 full weeks give 60, and the 6 remaining days starting on a Tuesday include 4 weekdays: 64 business days.
Public holidays such as Thanksgiving, Christmas and New Year’s Day fall in that period; subtract them for an exact count of working days.
Typical periods
| Period | Days |
|---|---|
| 1 week | 7 |
| 1 month | 28 to 31 |
| 1 quarter | 90 to 92 |
| 6 months | 181 to 184 |
| 1 year | 365, or 366 in a leap year |
| Business days in a year | about 260, before holidays |
Where day counts matter
Return windows, warranty periods, notice periods, interest calculations, visa stays and court deadlines are often written in days. Check whether the rule counts calendar days or business days, and whether the first or last day counts, since a one-day error can matter for a deadline.
Leap years
The calculator follows the Gregorian calendar, with a February 29 every year divisible by 4, except century years not divisible by 400. A period that spans February in a leap year is one day longer.