Korean age calculator
Korea has used three ways of counting age. Enter your date of birth to see all three: international age (만 나이), year age (연 나이), and the traditional counting age (세는 나이), plus the days left until your next birthday.
Since June 28, 2023, Korean laws and official documents use international age unless a specific law says otherwise. Some laws use year age instead. The Juvenile Protection Act, for example, stops treating people as minors from January 1 of the year they turn 19.
How to use
- Pick your date of birth.
- Check the reference date. It starts as today.
- Read your international age, year age, counting age, and days to your next birthday.
How it works
International age = reference year − birth year, minus 1 if this year's birthday has not yet arrived. The Korean Civil Act (Article 158) and the Framework Act on Administration (Article 7-2) count age this way, including the day of birth.
Year age = reference year − birth year, regardless of birthday, so everyone born in the same year has the same year age. Counting age = year age + 1.
For people born on February 29, the birthday is treated as March 1 in common years.
Example
Someone born on May 10, 2000 is, on May 9, 2026, 25 in international age, 26 in year age, and 27 in counting age, with 1 day to the next birthday. On May 10 they turn 26.
Someone born on February 29, 2000 is 24 through February 28, 2025 and turns 25 on March 1, 2025. In the leap year 2028 they turn 28 on February 29.
Good to know
- Since June 28, 2023, ages in Korean laws, contracts, and official documents mean international age unless a law says otherwise.
- Some rules, such as the age for buying alcohol and tobacco or for military service, use year age. Check the rule that applies to you.
- Results are for reference only.
Frequently asked questions
What is international age?
You are 0 at birth and gain a year on each birthday. This is the age used in most countries, and the default in Korean law since June 2023.
What is the traditional Korean counting age?
You are 1 at birth and everyone gains a year on January 1. It equals year age plus one. It is still heard in everyday conversation but is no longer used in law.
When does someone born on February 29 get older?
In common years there is no February 29, so this calculator moves the birthday to March 1, following the Korean Civil Act rule that a year ending in a missing day ends on the last day of that month.
Sources
Last updated: 2026-10-29