Age Calculator
Exact age in years, months and days.
Runs entirely in your browser. Nothing you enter or upload leaves your device.
What the age calculator does
This calculator works out the exact time between a date of birth and another date, in years, months and days. It also gives the same span as total months, weeks, days and hours, counts the days to the next birthday, and tells you the day of the week the person was born on.
It is useful for forms that ask for an exact age, for checking whether someone meets an age limit on a given date, for tracking a baby’s age in months or weeks, or for measuring any other stretch of time between two dates.
How to use the age calculator
- Enter the date of birth.
- The second date defaults to today. Change it to find someone’s age on a past or future date.
- Read the exact age, the totals in months, weeks, days and hours, the days until the next birthday and the weekday of birth.
Understanding the results
The calculator works with whole dates, not times of day. Total days counts the calendar days between the two dates, and total hours is simply that figure multiplied by 24. Total weeks shows full weeks with any days left over, such as 52 w 3 d.
Years and months follow the calendar: a month is complete only when the same day number comes round again, and the days after that are counted separately. When the second date is the birthday itself, the next birthday reads “Today!”.
Questions
How are months counted?
Full calendar months are counted first, then the remaining days. From 31 January to 28 February is 28 days, not one month, because the 31st has not been reached again.
What about birthdays on 29 February?
In years without a 29 February, the next birthday is shown as 28 February. Some countries use 1 March for legal purposes.
Does it count both the first and last day?
No. Total days is the difference between the dates, so 1 to 2 January counts as one day. Add one if you need to include both ends, as some leave and booking rules do.
Can I use it for dates that are not birthdays?
Yes. Put the start date in the first box and the end date in the second to measure any period, such as a tenancy or time in a job. The second date must not be earlier than the first.
Is my date of birth stored?
No. The calculation happens in your browser and nothing is saved or sent.