How to calculate age in years
Subtract the year of birth from the current year, and subtract one more if the birthday has not happened yet this year. A person born on 15 June 2000 is 26 on 1 November 2026, but only 25 on 1 March 2026. Subtracting the years alone would give 26 in both cases, which is wrong before the birthday.
If you only know the year of birth
Tick I only know the year of birth. Someone born in 2000 is one of two ages on any day of 2026: 26 if the birthday has already passed this year, and 25 if it has not. The tool shows both, because the year alone is not enough to give one answer.
Age in decimal years
For statistics and forms, age is sometimes given with decimals, such as 26.4 years. The calculator divides the days lived by 365.25, the average length of a year including leap years.
Next birthday
The tool shows the age you turn at the next birthday and the number of days to go. If today is the birthday, it says so.
Age on another date
Change Age at the date of to check the age on a past or future date, for example at the start of a course or a job, or on a closing date. Many forms ask for the age on a particular day rather than today.
Other ways of counting age
In international counting a person is 0 at birth. Some East Asian systems have counted a newborn as 1 and added a year at New Year. Read how age is calculated for the details.
Related calculators
For years, months and days at once, use the age calculator. See also age in months, age in days and date of birth from age.