Korean Age Calculator
This calculator shows your international age, year age and counting age in Korea for any date, with the days left until your next birthday and the days you have lived.
- International age (man-nai)
- –
- 0 at birth, one year older on each birthday. The standard in Korean law and official documents.
- Year age (yeon-nai)
- –
- Reference year minus birth year. Some Korean laws still count this way.
- Counting age (seneun-nai)
- –
- 1 at birth, one year older every January 1. The traditional everyday Korean age.
Enter a date of birth to see the result.
Your birth date is calculated in your browser only and is not stored.
For legal or administrative decisions, follow the rules of the responsible agency. Some laws use year age.
How to use the Korean age calculator
- Enter your date of birth.
- Leave the reference date as today, or change it to check your age on another date.
- Read your international age, year age and counting age in the result.
- Check the days until your next birthday and the number of days you have lived.
When to use it
- Checking your international age (man-nai) before you fill in a Korean form or contract.
- Finding out how old you, a K-pop idol or an actor would be in everyday Korean age.
- Comparing year age with international age for rules that count by birth year.
- Counting the days left until your next birthday.
Questions about Korean age
How is international age (man-nai) calculated?
Subtract your birth year from the current year. If your birthday has not come yet this year, subtract one more. You are 0 on the day you are born and you gain a year on each birthday.
What is the difference between international age, year age and counting age?
International age goes up on your birthday. Year age is the current year minus your birth year, so it goes up on January 1. Counting age, the traditional Korean age, is year age plus one: you are 1 at birth and you gain a year every January 1.
When did South Korea switch to international age?
On June 28, 2023. Amendments to Korea's Civil Act and its basic administrative law took effect on that day. Since then, age in laws, contracts and official documents means international age unless a rule says otherwise. The source is the Korean Ministry of Government Legislation.
Does Korea still use year age anywhere?
Yes. When the change took effect, the Korean government said that some rules stay as they were. The Military Service Act and the Youth Protection Act, which sets the age for buying alcohol and tobacco, count by year age. Children start elementary school in March of the year after they turn 6. We checked this against Korean government announcements on October 5, 2026. For a legal or administrative decision, check the current rule with the responsible agency.
How does it count age for people born on February 29?
In a leap year, the age goes up on February 29. In other years, this tool counts March 1 as the day the age goes up. This follows Article 160 of the Korean Civil Act: when the matching day does not exist in the month, the period ends on the last day of that month. For a legal decision, check with the responsible agency.
Is my birth date saved or sent anywhere?
No. The calculation runs in your browser. Your birth date is not sent to a server and is not stored.