Age Calculator
Calculate international age and year age
Year - Month - Day
Year - Month - Day
Age calculator
Computes international (full) age, nominal age, and Korean-style age in one go.
Enter birth date and reference date to get full age (used legally in many countries), nominal age (current year minus birth year), and Korean age (nominal + 1).
- Full age increases by one each birthday and is used on official documents in most countries.E.g. Born May 1, 2000, as of March 1, 2025: full age is 24.
- Korean age: everyone is 1 at birth and adds one on each Jan 1.E.g. Born in 2000, as of Jan 1, 2025: Korean age 26.
- Full age (international age)
- Full age is the number of complete years since birth. It is the standard for legal and administrative use in most countries.
- Nominal age
- Nominal age is (current year − birth year), often used in statistics and demographics. It does not account for whether the birthday has occurred this year.
Different ways of counting age
Most of the world counts age one way, but several East Asian systems count differently — which is why an age can legitimately differ by up to two years depending on the method.
Three counting systems
International age starts at 0 on the day you are born and adds a year on each birthday. This is the standard almost everywhere and the one used in legal and administrative contexts.
Nominal age is simply the current year minus the birth year, ignoring the birthday. Everyone born in the same year shares the same number.
Korean traditional age started at 1 at birth and added a year every New Year's Day, so a baby born on 31 December turned two the next day.
Korea's 2023 change
From 28 June 2023, amendments to Korean law standardised age references in statutes, contracts and official documents on international age unless a specific rule says otherwise.
The traditional counting method has not disappeared from conversation, and some Korean statutes still use nominal age, so asking someone's age in Korea can still be ambiguous.
Where nominal age still applies
Korea's Military Service Act uses nominal age: eligibility is tied to the calendar year in which someone turns 19, regardless of birthday.
The Youth Protection Act works the same way, so restrictions on alcohol and tobacco lift on 1 January of the year someone turns 19 rather than on their birthday. This is why the legal purchase date does not match the international-age birthday.
How the numbers diverge
Take someone born 10 May 1990, evaluated on 1 March 2026. Their international age is 35, nominal age 36, and traditional Korean age 37 — three different answers on the same day.
Evaluate the same person on 1 June 2026 and the birthday has passed, so international age becomes 36 and matches nominal age. The two differ only before the birthday.
Leap-day birthdays
People born on 29 February have no birthday in common years. Most jurisdictions treat 1 March as the legal date on which their age increases, though some systems use 28 February.
This rarely matters, but it can shift eligibility by one day for things like licences and age-restricted purchases, and different institutions may not agree.
| Method | Age · calculation |
|---|---|
| International age | 35 · birthday not yet reached this year |
| Nominal age | 36 · 2026 − 1990 |
| Korean traditional age | 37 · nominal age + 1 |
| Korean legal standard | International age (since 28 Jun 2023) |
| Military / youth statutes | Nominal age |
Frequently asked questions
- Did Korea abolish traditional age counting?
- It standardised legal and administrative references on international age in June 2023. Traditional counting is still used conversationally and was never banned.
- Why do Korean age limits not start on the birthday?
- Because the Youth Protection Act uses nominal age. Restrictions lift on 1 January of the year someone turns 19, before their actual birthday.
- When do international and nominal age match?
- From the birthday to the end of that calendar year. Before the birthday, international age is one lower.
- What about people born on 29 February?
- In common years most jurisdictions treat 1 March as the date the age increases, though some systems use 28 February. Institutions do not always agree.
- Which age should I put on official forms?
- International age, unless the form specifically asks for something else. That is the default in Korean law since 2023 and the norm internationally.