Korean Age Calculator
Calculate your international (만) age and year age from your birth date.
Based on Korea's 2023 unified-age law (만 나이).
What is Korean Age Calculator?
Korean Age Calculator works out your international (만) age and year age from your birth date, following Korea's unified-age law in effect since June 2023. Korea traditionally counted age differently, so this free calculator shows both figures: 만 age, the legal and everyday standard, and year age, still used by a few laws. It runs in your browser.
Key features
- International (만) age with birthday-passed adjustment
- Year age: current year minus birth year
- Follows Korea's unified-age law effective June 2023
- Instant result from a single birth-date input
- Notes where year age still applies (military service, youth protection)
How to calculate your Korean age
For decades, Korea juggled three different ways to count age at once, and the numbers could differ by two. Since the unified-age law took effect on 28 June 2023, the international system (만 나이, "man age") is now the legal and everyday standard nationwide. This calculator takes one input — your birth date — and shows both figures that still matter, so you can fill in a Korean form or answer "몇 살?" without doing the math in your head.
The two ages this tool shows
- International (만) age — the same age used everywhere in the world: it's your age since your last birthday. The tool computes
this year − birth year, then subtracts 1 if your birthday hasn't arrived yet this year. Someone born on 1 May 1990, calculated in early 2026, is 35 until 1 May and 36 after it. This is now the number for contracts, medical and legal documents, and normal conversation. - Year age (연 나이) — simply
this year − birth year, ignoring the month and day. Everyone born in the same calendar year shares this number, and it ticks over for everyone at once on 1 January.
Why year age still exists
Even under the unified-age law, a handful of statutes deliberately use year age because it's simpler to administer for a whole birth-year cohort at once. The two most common are military conscription (병역법) and youth protection (청소년보호법) — the latter is why the rule for buying alcohol and tobacco is based on birth year, so a Korean turns "of age" for that purpose on 1 January of the year they reach 19, not on their actual birthday. Knowing both numbers tells you which rule a given form is applying.
Using the tool
Pick your date of birth from the date field (it won't let you choose a future date). Both ages appear instantly, with the 만 age highlighted as the primary figure and the year age shown beside it. The calculation is plain date arithmetic done in your browser against today's date — nothing you enter is sent anywhere.
What happened to "Korean age"
The old 세는 나이 ("counting age"), where a newborn started at 1 and everyone gained a year every New Year, is what made Koreans up to two years "older" than their international age. That count is what the 2023 reform retired from official use. This tool doesn't display it, because outside of casual habit it no longer has any legal standing — if a form or person asks your age today, they mean 만 나이 unless a specific law (like the two above) says otherwise.
Frequently asked questions
- What is the difference between 만 age and year age?
- 만 (international) age is your age since your last birthday: this year minus your birth year, minus 1 if your birthday has not come yet this year. Year age (연 나이) is simply this year minus your birth year, ignoring month and day, so it ticks over for everyone at once on 1 January.
- Since the 2023 law, which age should I give on Korean forms?
- 만 나이 has been the legal and everyday standard nationwide since the unified-age law took effect on 28 June 2023, so use it unless a specific law says otherwise. This calculator highlights 만 age as the primary figure for exactly that reason.
- Why does the tool still show year age at all?
- A few statutes deliberately use year age because it is simpler to administer for a whole birth-year cohort, most notably military conscription (병역법) and youth protection (청소년보호법). That is why the rule for buying alcohol and tobacco is based on birth year, so a person counts as of age from 1 January of the year they reach 19, not on their actual birthday.
- What happened to the old 'Korean age' that made people a year or two older?
- That was 세는 나이 ('counting age'), where a newborn started at 1 and everyone gained a year each New Year. The 2023 reform retired it from official use, so this tool does not display it; outside of casual habit it no longer has any legal standing.
- Is my birth date sent anywhere?
- No. Both ages are computed locally in your browser with standard date arithmetic against today's date. The date field also will not let you pick a future date.
Privacy
Both age figures are computed locally from the birth date you enter, using standard date arithmetic; nothing is sent to a server.