Korean age calculator

Korea counted age three different ways, and the law changed in June 2023. Put your birthday in and see all three — and which one someone means when they ask.

What changed in 2023

Until June 2023 a Korean could honestly give three different answers to how old they were. The law now fixes the international count as the default for anything official, but the other two have not vanished — year age still decides school years and the legal drinking age, and the traditional count is still what a grandmother will use.

Why the old count exists at all

In the traditional system you are one year old the day you are born, and everyone gains a year together on New Year’s Day rather than on their birthday. A baby born on 31 December turns two the next morning. That is not a joke, and it is why the law was changed.

The 2023 change

On June 28, 2023, the revised Civil Act and the Framework Act on Administration took effect. From that day, Korean law counts age in the international way for most purposes. The change was made by law, not by custom. It did not erase the older counts. Some laws still use them, and people still use them in everyday talk.

The three ways

There are three counts in use. Each one gives a different number for the same person.

• 만 나이 (international age)

  You are 0 at birth. You gain a year on your own birthday. This is the legal count now.
• 연 나이 (year age)

  The current year minus your birth year. You gain a year on January 1, whatever your birthday is.
• 세는 나이 (counting age)

  You are 1 at birth. You gain a year on January 1. This is the traditional count, and the one a grandmother will use.

A worked example

Take someone born on December 31, 2010. On January 1, 2026, the three counts give three answers. The international count is 15, because the birthday has not come round yet in 2026. The year count is 16, since 2026 minus 2010 is 16. The traditional count is 17, one more than the year count. The international count will not reach 16 until December 31, 2026, which is why a baby born at the end of the year is two years old the next morning by the traditional count.

Take someone born on June 1, 2000. On October 14, 2026, the international count and the year count are both 26, because the birthday has already passed this year. The traditional count is 27.

Where the old counts still apply

Some laws still count by year age. The military service law is one. The 2023 change did not alter those rules, so for any specific legal question, read the text of that law. School grades are set by birth year as well, so classmates are usually born in the same calendar year, and that is a question of grade, not of legal age.

Why people ask your age

Asking someone’s age is normal in Korea, and it is usually about how to address them. The word you use for an older sibling or a senior colleague depends on the answer, so many Koreans will ask within the first few minutes of meeting. You can answer with the number you know, and they will adjust. If you are not comfortable, say you would rather not give it, and most people will move on.

The grammar follows the answer too. Speech level and the polite forms depend on who is older, so the question is not only small talk. The speech levels guide explains how.

Korean age in a sentence

In speech, the age is said with a native number up to ninety-nine, and the counter word is 살. A person who is twenty-five says 스물다섯 살. Someone who is one or two years old says 한 살 or 두 살, with the number changed as before a counter. The polite way to ask is 나이가 어떻게 되세요. The answer comes back as a number and 살, and that is the number a Korean will mean in ordinary talk.

When a sentence is about a legal matter, the number may be the international count even if the speaker used a traditional one at dinner. Two people can give different numbers for the same birthday and both be right, because they were counting differently.

How the calculator works

Put in your birth year, month and day. The tool works out the international count for the date you choose, the year count from the birth year, and the traditional count from the year count. The traditional count is always one more than the year count. The international count matches the year count once your birthday has passed, and is one less before it. The calculation uses your birth date only, and nothing is stored.