Exact age, not just years
Most of the time we say an age in whole years, but some situations need more detail. The calculator gives the age in years, months and days, so you know not only that someone is 34, but that they are 34 years, 7 months and 12 days old.
It takes care of the details that make this tricky by hand, such as months of different lengths and leap years, so you don't have to count on your fingers.
The result updates as soon as you change a date, so you can try several dates of birth or reference dates in a row, for example to fill in the ages of everyone in a family or a team.
Age on a specific date
By default the age is calculated as of today, but you can change the "As of" date to any day. That answers questions like how old a child will be on the first day of school, how old you will be on the day of a trip, an exam or a race, or how old someone was on a date in the past.
Forms and applications often ask for the age on a reference date rather than on the day you fill them in. Scholarships, sports leagues, school enrollment and some contests work this way. When there is an official rule, read it and use its exact reference date.
Babies, pets and anniversaries
Parents count a baby's age in months for checkups, vaccines and milestones, and the calculator gives the months and days directly. It works just as well for the age of a pet, the time since a wedding or a company's founding, how long you have worked somewhere, or how many years a building or a car has.
For a count in total days or weeks between two dates, for example how many days you have been alive, use the "Days between two dates" mode of Date calculator.
Teachers and coaches also use it to check whether a student or a player falls within an age group on the cutoff date of a league or a competition, before filling in a registration form.
Private and free
This page is the exact age mode of Date calculator, which also counts days between dates, adds or subtracts days and counts business days with holidays. Everything is calculated in your browser: dates of birth are personal data, and they are not sent or saved anywhere. It is free, with no account, on phones and computers.