Age Calculator — Free Online Tool

🎂 Age Calculator

Working out someone's exact age from a date of birth sounds simple until you have to account for how many days are in each month and whether the current year is a leap year — which is exactly the kind of fiddly arithmetic this tool takes care of instantly. Enter a date of birth and this calculator returns the exact age in years, months and days as of today (or any date you choose).

It's handy for filling government forms that need an exact age, checking eligibility cut-offs, working out a baby's age in months and days, or simply satisfying curiosity about how many total days you've been alive.

How to use the Age Calculator

Enter the date of birth.
Optionally change the 'as of' date — it defaults to today.
View the exact age in years, months and days, total days lived, and days remaining until the next birthday.

How age is calculated

The calculator finds the difference between the 'as of' date and the date of birth, correctly borrowing days and months (accounting for the actual number of days in each calendar month and for leap years) so the years/months/days breakdown always reflects real calendar durations rather than a rough estimate based on fixed 30-day months.

Frequently asked questions

Does this account for leap years?

Yes. The calculation uses actual calendar dates, so February 29 in leap years and the varying number of days per month are handled correctly rather than assuming every month has 30 days.

Can I calculate age as of a past or future date instead of today?

Yes — change the 'as of' date field to any date, past or future, to see what someone's age was, or will be, on that specific date.

Why does the total number of days matter?

Some official processes and milestone trackers (like '10,000 days old' celebrations, or infant age tracking in days/weeks) need age expressed purely in total days rather than years/months/days, which this tool also shows.