Help & FAQ
How to use the Date Calculator
How to use the date calculator
Days between two dates
- Choose a start date and an end date.
- Decide whether the end date should be counted (see the FAQ below).
- Read the total days, plus the breakdown into weeks, weekdays, and years, months and days.
Adding or subtracting time
- Pick a start date, choose add or subtract, and enter a whole number of days, weeks, months or years.
- The resulting date and its weekday appear straight away.
Counting rules
- Exclusive by default: the number of days is the number of midnights between the two dates.
- Inclusive option: adds one day so both the start and end date are counted.
- Weekdays: Monday to Friday, using the same inclusive or exclusive setting.
- Months and years: calendar-based, with the day clamped to the end of shorter months.
- Time zones: dates are treated as whole calendar days, so daylight-saving changes never add or remove a day.
Examples
- 90 days after 15 January 2025 is 15 April 2025.
- From 1 January to 31 December 2024 is 365 days, or 366 counting both dates.
- Six months before 31 August is 28 or 29 February.
Should I include the end date?
It depends on what you are counting. For the length of a hotel stay or the time until an event, leave it off — 1 to 3 March is 2 nights. For a holiday or contract where both the first and last day count, tick "Include the end date" — 1 to 3 March is then 3 days.
What happens when I add a month to 31 January?
There is no 31 February, so the result is the last day of February (28 or 29). Adding months always keeps the day number when it exists and otherwise uses the last day of the month.
Are public holidays excluded from the weekday count?
No. Weekdays are Monday to Friday. Public holidays differ by country and region, so subtract them yourself if needed.