Korean Age Calculator — International (Man) Age
Date & TimeKorean Legal Age Calculator is a date tool that calculates legal age from a birth date.
What is it
Korean legal age ("man-nai") starts at 0 on the day of birth and increases on each birthday — the same as international age. Since the age-unification amendments to the Administrative Basic Act and Civil Act took effect on 28 June 2023, statutes, contracts, and administration in Korea use this age by default. It can be one or two years lower than the traditional counting age (1 at birth, +1 every New Year), and some laws such as the Military Service Act still use year age (current year minus birth year).
How to use
- 1Enter the date.
- 2Press calculate.
- 3Check the result and reference date.
Reference
| Birth year | Before 2026 birthday | After |
|---|---|---|
| 1990 | 35 | 36 |
| 1995 | 30 | 31 |
| 2000 | 25 | 26 |
| 2005 | 20 | 21 |
| 2010 | 15 | 16 |
Sources & standards
- Administrative Basic Act — age calculation standard (man-nai unification) - Korea Law Information Center
- ECMAScript Language Specification - Ecma International
FAQ
How is Korean legal age calculated?
Subtract the birth year from the current year, then subtract 1 more if the birthday has not yet passed this year — identical to international age.
What changed with the 2023 age-unification law?
From 28 June 2023, Korean statutes, contracts, and administration interpret age as international (man) age by default, replacing the traditional counting age in most contexts.
What is Korean counting age?
The traditional system where you are 1 at birth and gain a year every New Year — one to two years higher than international age. It is still used colloquially.
Is my birth date sent to a server?
No. This tool runs in your browser and does not send input to a server.