Legally South Korea moved to international age in 2023, but the traditional count persists in everyday speech.

Date & time Age

Korean age calculator

Date of birth

On this date

Korean age —

The same age, other ways

Exactly —

In months —

In weeks —

In days —

In hours —

Born on a —

Next birthday —

Days to go —

Turning —

Note Enter a date of birth

One at birth · a year every 1 January

Traditional Korean age counts you as one at birth and adds a year every 1 January rather than on your birthday. Someone born on 31 December is therefore two in Korean age the following day, while being one day old internationally.

How Korean age works

1 Enter the date of birth.

2 Read the Korean age and the international one.

3 The gap is one or two years depending on whether your birthday has passed.

4 South Korea standardised on international age in law in 2023.

South Korea legally moved to international age in June 2023, ending a long-standing situation where three different age systems coexisted — traditional, international, and a "year age" used for school entry and military service. The traditional count has not disappeared from everyday speech, and it still shapes social hierarchy, since Korean speech levels depend on relative age. The calculation remains worth knowing even though the legal position has changed.

Questions

How is Korean age calculated? −

You are one at birth, and everyone gains a year on 1 January regardless of birthday.

Why the difference of one or two? +

Is it still used? +

What about someone born on 31 December? +

Is this used elsewhere? +

Was this tool any good?

INTERNAL SIGNAL ONLY · WE USE IT TO FIND TOOLS WORTH REBUILDING