How to calculate age
- Enter the date of birth.
- Keep “Age on this date” as today, or choose another date, for example to check eligibility on a deadline.
- Click Calculate age.
- Read the exact age and the extra details below it.
How exact age is worked out
Many quick age calculators divide the number of days by 365.25, which can be off by a day around birthdays. This age calculator counts real calendar months instead: it finds the number of whole months between the two dates, then counts the remaining days. When a birthday falls on a day that doesn’t exist in a shorter month, such as the 31st, it uses the last day of that month, the same convention used in most legal and financial calculations.
People born on 29 February are treated as having their birthday on 28 February in years that aren’t leap years. Total days are counted precisely, including every leap day in between. Dates in the future are rejected, and invalid dates such as 31 April are caught before calculating.
When you might need it
- Checking age requirements for school admission, sports or exams.
- Filling in forms that ask for age in years and months.
- Calculating the age of a pet, a building or a company.
- Fun facts: how many days old you are, or the weekday you were born.
Age calculator FAQ
Is my date of birth stored?
No. The calculation happens in your browser and nothing is saved or sent.
Why might another calculator give a different answer?
Some tools use average month or year lengths. This one uses actual calendar dates, which is more accurate.
Does it account for time zones or birth time?
No. It works with whole dates, which is what age calculations normally require.