How it works
Two questions, one tool: how long between two dates, and what date falls a number of days from another.
- For a gap, enter both dates — the answer comes in days, and in years, months and days.
- For a future or past date, enter the starting date and the number of days to add or subtract.
- Leap years are handled by the calendar, so February never trips it up.
Watch the endpoints: a stay from the 1st to the 5th is four nights but five days if you count both ends. Contracts and notice periods usually mean whole days between the dates, not inclusive counting.
Examples
Worked examples:
- 1 January to 31 December 2026: 364 days between them, 365 counting both ends.
- 90 days from 22 September 2026: 21 December 2026.
- A 30-day notice period starting Monday ends on the Wednesday four weeks and two days later — count days, not weeks.
For an exact age, use the age calculator; for a fixed number of days ahead, days from today.
Date Calculator: frequently asked questions
- How many days are between two dates?
- Subtract the earlier date from the later one. The result excludes the end date; add 1 if you want to count both the start and end days.
- How are business days counted?
- Weekdays (Monday to Friday) between the two dates are counted; public holidays are not excluded.
- What happens when adding a month to 31 January?
- JavaScript date rules roll over to early March in non-leap years (31 Feb doesn't exist), so check month-end results.