Your birth year is the reference year minus your age. If your birthday has not occurred yet in that year, subtract 1 more year.
Find your birth year
The initial age is an example. Change the inputs to calculate your birth year.
Birth year
2007 or 2008Use the later year if the birthday is on or before the reference date. Otherwise, use the earlier year.
Your inputs stay in this page. This tool does not send or save them.
How is the birth year calculated?
Subtract your age from the year of the reference date. If your birthday is after the reference date in that year, subtract 1 more year.
A birthday on the reference date counts as passed. Your age increases on your birthday.
If you do not know whether your birthday has passed, two consecutive birth years are possible. On December 31, every birthday has passed, so only the later year is possible.
If I am 18, what year was I born?
On October 26, 2026, a person aged 18 with a birthday on or before October 26 was born in 2008.
A person aged 18 with a birthday after October 26 was born in 2007. Without the birthday, the birth year is 2007 or 2008.
Birthday month and day
Select your birthday month and day to get one birth year. The calculator compares that birthday with the reference date.
A February 29 birthday uses February 28 in common years, as in the exact-age calculator. For example, age 18 on February 28, 2026, gives 2008.
A February 29 birth date must be in a leap year. Age 17 on October 26, 2026, gives 2009, which has no February 29. The calculator then shows that no February 29 birth date gives this age.
Calculation limits
Enter a whole age from 0 through 8399. The calculator does not accept birth years before 1600. This tool uses Gregorian dates only.
The reference date is today on your device. Before the calculator loads, the example uses October 12, 2026. This tool does not calculate legal age.