Date Difference Calculator: Days Between Dates
By Hesaplayıcı
The date difference calculator finds the number of days between a start date and an end date. Choose whether the end day counts. It also gives the result as full weeks and remaining days, as years, months and days, and as Monday–Friday business days. Public holidays are not removed.
Worked example: 1 January to 31 December 2026, end day included
Days
365 days
- Full weeks
- 52 weeks
- Days after the full weeks
- 1 days
- Years
- 1 years
- Months
- 0 months
- Days after the full months
- 0 days
- Business days (Monday–Friday)
- 261 days
Step by step
Days
days = end − start + 1
days = 2026-12-31 − 2026-01-01 + 1 = 365 days
Full weeks
full weeks = ⌊days / 7⌋
full weeks = ⌊365 / 7⌋ = 52 weeks
Days after the full weeks
remaining days = days − 7 × full weeks
remaining days = 365 − 7 × 52 = 1 days
Business days (Monday–Friday)
business days = days − Saturdays and Sundays
business days = 365 − 104 = 261 days
How to use
- Enter the Start date, the first day. It counts.
- Enter the End date, the last day. It cannot be before the start date.
- Choose Count the end day? Choose “Yes” to count the end day too, which adds one day.
- Press Calculate.
Formula
Days = end − start (+ 1 when the end day counts)Full weeks = ⌊days / 7⌋Remaining days = days − 7 × full weeksBusiness days = days − Saturdays and Sundays
Start and end are the dates you enter. ⌊ ⌋ rounds down. Saturdays and Sundays are the weekend days among the days counted.
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: 15.01.2010 to 18.03.2011 is 1 year, 2 months and 3 days, and 31.01.2023 to 01.03.2023 is 1 month and 1 day. February has 29 days in leap years.
Worked example
The worked example on this page counts from 1 January 2026 to 31 December 2026 with the end day included, which is the whole of 2026. The steps give the days, the full weeks, the remaining days and the business days.
Limits
Public holidays, religious holidays and half-day holiday eves are not removed from the business days; only weekends are. Where Saturday is a working day, the number of working days is different. Time of day and time zones are not used; each date is a calendar day. An end date before the start date gives an error.
Frequently Asked Questions
Does the number of days include the end date?
Not by default: the start day counts and the end day does not. Choose “Yes” to count the end day too, which adds one day.
Are public holidays removed from the business days?
No. The calculator removes only Saturdays and Sundays; public and religious holidays count as business days.
How many months are there from 31 January to 1 March?
Full months come off first, then the remaining days are counted. 31.01.2023 to 01.03.2023 is 1 month and 1 day, or 29 days.
Are leap years taken into account?
Yes. February has 29 days in leap years. Years divisible by 4 are leap years; century years not divisible by 400, such as 1900, are not.
Calculation rules
- The start day counts and the end day does not. Choose “Yes” to count the end day too, which adds one day.
- 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: 15.01.2010 to 18.03.2011 is 1 year, 2 months and 3 days; 31.01.2023 to 01.03.2023 is 1 month and 1 day.
- Business days are Monday to Friday. Public holidays, religious holidays and half-day holiday eves are not removed.
- Leap years have 366 days: years divisible by 4, except century years not divisible by 400. Time of day and time zones are not used.
- The end date cannot be before the start date; enter the earlier date first.