Age calculator
Exact age in years, months and days from a date of birth, plus total days and the next birthday.
How it works
Enter a date of birth to get the exact age today in years, months and days, along with the total number of days lived and how long until the next birthday.
Calendar age is fiddlier than it looks because months have different lengths. The convention used here — and by essentially every legal system — is that you become a year older on the anniversary of your birth date, with months counted as whole calendar months rather than as fixed 30-day blocks.
People born on 29 February are the genuine edge case. In most jurisdictions a leap-day birthday is treated as falling on 1 March in common years for legal purposes, though 28 February is used in some. This calculator counts the anniversary as 1 March in non-leap years.
This tool runs entirely in your browser. Nothing you enter is sent to a server, logged or stored, and the page keeps working with the network disconnected.
Common questions
- How do you calculate exact age?
- Count whole years from the birth date to today, then whole calendar months, then remaining days. Because months vary in length, counting in 30-day blocks gives a different and less useful answer.
- How does a 29 February birthday work?
- In common years there is no 29 February, so the anniversary is treated as 1 March in most jurisdictions. A person born on a leap day has a birthday every year; only the date it falls on shifts.
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