Date calculator
Four date tools in one place: days between two dates, adding or subtracting time, age from a birth date and the day of the week.
How to use it
- Pick a tab: "Days between dates", "Add or subtract", "Age" or "Day of the week".
- Enter the dates. Each tab has a "Today" button for the current date.
- For a count of days, tick "Count the end date too" or "Weekdays only" if you need them.
- Read the result and click the copy button next to it to take the number or date with you.
What it does
Days between two dates
Get the total days plus years, months and days, weeks and days, hours, weekdays and weekend days, all from one pair of dates.
Add or subtract time
Add or subtract years, months, weeks and days from a date. A month added to 31 January lands on the last day of February.
Age to the day
Enter a birth date to see age in years, months and days, total days lived and the date and countdown of the next birthday.
Weekdays only
Count Monday to Friday only, or add a number of working days that skips every Saturday and Sunday.
Day of the week and more
Find the weekday of any date together with its day of the year, ISO week number, quarter and whether the year is a leap year.
Good to know
The calculator counts whole calendar days, so daylight saving changes never add or remove a day. Leap years are handled by the rules of the Gregorian calendar, which means 29 February exists in 2024 and 2028 but not in 2100.
"Days between" normally leaves out the end date, so 1 January to 2 January is one day. Tick "Count the end date too" when both days should be included, for example when counting the days of a trip or a leave period. The years, months and days line is worked out the way people usually say it: the number of full months, then the days left over.
Questions and answers
How many days are there between two dates?
Enter the start and end date on the "Days between dates" tab. The headline figure is the number of days between them, with the end date left out unless you tick the box.
How do I count only working days?
Tick "Weekdays only (Mon–Fri)". Public holidays are not known to the tool, so subtract those yourself.
What happens when I add a month to 31 January?
The result is the last day of February, which is 28 or 29 February depending on the year.
How is age calculated?
It counts completed years, then completed months, then the days left over since the last monthly anniversary of the birth date.
Can I calculate age on a past or future date?
Yes. Change the "Age on" date to any day after the birth date.
Are my dates stored anywhere?
No. All calculations happen in your browser, and only the tab you last used is remembered on your device.