How to count days between dates
Choose how to count
Choose a start and end date, then press Calculate. By default, the result shows how many days must pass from the first date to the second. The start date is excluded and the end date is included. Select Include both dates to count every date in the interval.
One night or two days?
From 1 to 2 January, 1 day elapses. Including both dates gives 2 calendar dates: 1 and 2 January. For the same date, the results are 0 and 1 respectively. These answer different questions, so the counting rule always appears next to the result.
Adding and subtracting days
In the second mode, enter a date and a whole number of days. A positive number moves forward and a negative number moves back. Zero leaves the date unchanged. 31 December 2025 plus 1 day is 1 January 2026. 1 March 2024 minus 1 day is 29 February 2024.
February and leap years
From 28 February to 1 March 2024, 2 days elapse; in 2025, only 1 day does. In the Gregorian calendar, years divisible by 4 are leap years, except years divisible by 100 unless they are also divisible by 400. So 2000 was a leap year, while 1900 and 2100 are not.
Weekends, holidays and clock changes
We count calendar dates, not the hours between midnights. Daylight saving time does not change the result. Weekends and holidays count just like other days. The tool does not use local holiday calendars.
Example: planning a trip
From 10 to 15 June, the difference is 5 days. Including both dates counts 6 calendar dates. This does not replace hotel booking rules: hotels may charge by the night and set their own check-in times.
Example: the date in 30 days
Starting from 1 April 2025, adding 30 days gives 1 May 2025. This is not a general rule for adding a month: months have different lengths. Adding 30 days to 31 January may give a different result from adding one month.
Limits and responsible use
We support years 0001–9999 using the same Gregorian rules throughout, including before the calendar was introduced. Local historical calendar changes are not reconstructed. The tool does not automatically calculate legal, official, tax or medical deadlines. Check the rules that apply to your situation and country.
Does reversing the dates give the same result?
We do not show an ordinary positive difference for a reversed interval. First correct the order or choose Swap dates. This makes it clear which date you are counting from.
Sources for calendar rules
Calendar rules checked on 30 October 2026. Examples and explanations are original.