Korean Age After the 2023 Law: Which Age Where?
Gizke Team · Published · Reading time: 3 minutes
Korea used to answer “how old are you?” with a different number than most of the world. Since the Age Unification Act of 28 June 2023, everyday life and most legal forms use 만 나이 — the same birthday-based age you would give abroad. Two older systems are still around, though, and some rules still cite them. This guide walks through all three with a worked example, then points you at a calculator that stays in your browser.
On this page
Use the Korean age calculator if you only need the numbers; keep reading if you want to know which number a form is asking for.
The three systems in one example
Take a birth date of 15 December 2000 and a reference day of 1 November 2026:
| System | Korean name | Result | How it is counted | | --- | --- | ---: | --- | | International | 만 나이 | 25 | Full years since the birthday; drops one year until the birthday arrives | | Year age | 연 나이 | 26 | Calendar year − birth year (birthday ignored) | | Traditional | 세는 나이 | 27 | 연 나이 + 1 (you start at 1 at birth; everyone ages up on New Year’s Day) |
So the same person can honestly say 25, 26 or 27 depending on the system. That is why forms now usually spell out 만 나이.
What the 2023 law changed
Before mid-2023, “Korean age” in casual speech usually meant 세는 나이. The unification act made 만 나이 the default for civil life and most statutes. Traditional age did not disappear from culture — birthdays, banmal/jondaetmal talk and older relatives may still use it — but it is no longer what a bank or hospital should assume.
Some areas still lean on 연 나이 or school-year rules: parts of alcohol and tobacco regulation, conscription paperwork, and elementary-school entry. Treat any summary table (including ours on the calculator page) as a pointer to the official text, not a substitute for it.
Worked edge cases
Birthday not yet this year. Born 1 March 2000, reference 28 February 2026 → 만 25, 연 26, 세는 27. On 1 March 2026, 만 becomes 26.
29 February births. In a non-leap year the birthday is treated as 1 March (민법-style period counting). Born 29 February 2000, reference 28 February 2027 → birthday not yet reached; on 1 March 2027 it has.
“How old was I on that day?” Change the reference date on the calculator instead of editing your birth date.
Which age to write on a form
- Read the form. If it says 만 나이 / full age / international age, use that.
- If it only says “age” on a modern Korean government or company form, 만 나이 is the safe default after 2023.
- For school entry, military service, or licensed sales of alcohol/tobacco, open the agency’s current notice — they may still define the threshold in 연 나이.
- Visa and foreign forms almost always want international age; do not add a year for “Korean age” unless the form says so.
Zodiac animal (띠)
The animal cycle follows the birth year ((year − 4) mod 12), the same 12-animal loop as the Chinese zodiac year. It is shown for orientation only — not an astrology claim — and may later link to a dedicated zodiac tool.
Privacy
Ages are computed from the dates you type. Nothing is uploaded; you can disconnect after the page loads and the calculator still works.
Quick checklist
- Need one number for a Korean form dated after June 2023? Start with 만 나이.
- Comparing with older relatives who “age up” at New Year? They may still mean 세는 나이.
- Unsure about alcohol, school or conscription? Prefer the statute over a blog table.
- Want the three numbers plus days to your next birthday? Open the Korean age calculator.