Days Between Dates Calculator
Count the days between two dates — with weeks, months, business days and hours — or add days to a date and count down to any day.
Dates use your device’s calendar. Business days are Monday to Friday.
More date calculators
Each one is set up for one question about dates.
How to count the days between two dates
The number of days between two dates is the end date minus the start date. By default the start day is counted and the end day is not — the same way you count nights in a hotel. From 1 March to 5 March is 4 days.
days including both dates = end date − start date + 1
Tick Include the end date when both days count, for example for the length of a holiday, a course or a contract. Then 1 March to 5 March is 5 days.
What the calculator shows
- Days between the dates, and the same span in years, months and days.
- Weeks and remaining days, and the number of hours.
- Business days (Monday to Friday). Tick the public holiday option to skip the holidays of the US, the UK, Denmark or Poland as well.
The other two tabs add or subtract days, weeks, months, years or business days from a date, and count down from today to any date.
Counting months and years
Months have 28 to 31 days, so “1 month” is measured on the calendar: from 15 January to 15 February is one month, from 31 January the calculator moves to the last day of February. Leap years add 29 February, which is why 1 January 2028 to 1 January 2029 is 366 days.
Counting by hand
To count days without a calculator, count the days left in the start month, add the full months in between (30 or 31 days, February 28 or 29), and add the day number of the end date. 10 April to 20 June: 20 (rest of April) + 31 (May) + 20 = 71 days.
Frequently asked questions
How many days are between two dates?
Subtract the start date from the end date. The calculator does it for you and shows the result in days, weeks, months and business days.
Does the calculator include the start and end date?
It counts the start date but not the end date, like counting nights. Tick “Include the end date” to count both, which adds one day.
How many business days are between two dates?
Count the days from Monday to Friday. The calculator shows business days for every period and can skip public holidays of the US, the UK, Denmark or Poland.
How many days are in a year?
365 days, or 366 in a leap year. Years divisible by 4 are leap years, except century years not divisible by 400 — 2000 was a leap year, 2100 will not be.