How do I count the days between two dates?
- 1Pick what you want to work out: days between two dates, adding or subtracting time, or a countdown.
- 2Enter the dates — the start date begins as today.
- 3For a booking, leave or a contract, tick "Include the end date" so both the first and last day count.
- 4Read the result in days, weeks, months and working days.
How are days between dates calculated?
- 01Days between = end date − start date (+ 1 if the end date is included)
- 02Weeks = days ÷ 7, with the days left over
- 03Working days = days that fall on Monday to Friday
- 04Date + months = same day of the month, or the month's last day if it is shorter
Days between two dates are counted as whole calendar days, so 1 January to 31 January is 30 days. Most people count it that way for ages, deadlines and "days from now". When both the first and the last day count — leave, rentals or event days — tick "Include the end date" and the count goes up by one.
Working days are the Monday–Friday days in the range. Public holidays are not taken out because they differ by country and region, so subtract them yourself if they apply.
When adding months or years, the day of the month stays the same. If the new month is too short — 31 January + 1 month, or 29 February + 1 year — the date stops at the last day of that month. Years are added first, then months, then weeks, then days.
Good to know
- Notice periods and deadlines often say "within 30 days" — use Add with 30 days to find the exact date.
- For visa stays, leave and rentals, check whether the rules count the first and last day, and tick "Include the end date" if they do.
- Working days don't include public holidays — subtract your country's holidays from the result.
- A week is always 7 days, but a month is 28 to 31 days, so "3 months" and "90 days" are not the same.
Date calculator — common questions
How many days are there between two dates?
Enter both dates in "Days between dates". The answer is the number of calendar days from the start to the end; tick "Include the end date" to count both days.
Does the day count include the start and end date?
By default it counts the start date but not the end date (1 to 2 January is 1 day). Ticking "Include the end date" adds one, so both days count.
How do I count working days between two dates?
The "Working days" line counts Monday to Friday in the range. It doesn't know public holidays, so take those off yourself.
What date is 90 days from today?
Choose "Add or subtract", leave the start date as today, enter 90 in Days and read the result date and its weekday.
What happens when I add one month to 31 January?
February is shorter, so the result is the last day of February — 28 February, or 29 February in a leap year.
How many days until Christmas or New Year?
Choose "Days until" and tap Christmas or New Year. The countdown always uses the next one to come.
Sources
Formulas last reviewed: September 30, 2026 ·How we check our formulas