Age Calculator
Find an exact age in years, months, and days, and a countdown to the next birthday.
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How to calculate an exact age
- Enter the date of birth.
- Leave As of on today, or pick another date to find an age on that day.
- Read the age in years, months and days, and the days left until the next birthday.
About this tool
The years/months/days breakdown counts a full year only once the birth month and day have both been reached — the same convention used for legal age. Everything is computed from calendar dates only (no time-of-day or time zone involved), so the result is the same no matter where in the world you or the "as of" date are.
Nothing entered here is sent to a server — the entire calculation runs as JavaScript in your browser tab.
Questions about calculating age
How is an exact age worked out?
Count the full years since the birth date, then the full months since the last birthday, then the days left over. A year only counts once the birthday itself has been reached.
How old will I be on a particular date?
Change the As of date to that day. It works for dates in the past too, such as someone’s age when an event happened.
Does the time zone or time of birth matter?
No. The calculation uses calendar dates only, so the answer is the same wherever you are. For an age in hours or minutes, use the age in days, hours and minutes tool.
Why do months make age calculations awkward?
Months have 28 to 31 days, so “1 month” isn’t a fixed length. That’s why the age is given as full years, full months and the remaining days.