Is this calculator free to use?

Yes, completely free — no account, no subscription, and no usage limits.

Is my birth date uploaded to a server?

No. All calculations happen locally in your browser. Your date of birth is never sent to any server.

Does it work offline?

Yes. Once the page is loaded, it works with no internet connection — useful when traveling or in restricted networks.

What is the difference between 만 나이 and 세는나이?

만 나이 counts completed years from birth (the international standard, now Korea's legal age since June 2023). 세는나이 starts at 1 at birth and adds 1 every January 1st regardless of birthday, so it can be 1-2 years higher.

What is 연나이 and when is it used?

연나이 is simply the current year minus your birth year — no birthday check. It is used in some Korean laws and educational contexts such as school grade placement.

Which age do Korean offices and hospitals use now?

Since the age-counting law took effect on 28 June 2023, 만 나이 - the international count - is the default in laws, contracts and administrative paperwork unless a specific statute says otherwise. Two well-known exceptions still run on 연나이: school entry year and military conscription screening. That is why this tool shows all three numbers side by side rather than picking one for you.

Why does my Korean age jump on New Year's Day but my international age does not?

세는나이 counts you as one at birth and adds a year every 1 January, so everyone ages together no matter when their birthday falls. 만 나이 only increases on the birthday itself. That is why the gap between the two numbers is two years before your birthday in a given year and one year after it.

🇰🇷 Korean Age Calculator (만 나이 · 세는나이 · 연나이)

Instantly see all three Korean age systems — 만 나이 (international/legal), 세는나이 (traditional counting age), and 연나이 (year age) — by entering your birth date. Free and runs entirely in your browser; nothing is uploaded or shared.

Enter your birth date

Date of birth

🇰🇷

Enter your birth date above to see all three Korean age systems at once.

Private by design. This tool runs entirely in your browser — nothing you enter is uploaded or stored, and it works offline.

About

Korea officially adopted 만 나이 as its sole legal age standard in June 2023, replacing two older systems still common in daily life. This calculator shows all three side by side — with the days remaining until your next birthday — so you always know which number applies in each context. Because it runs 100% client-side, your date of birth never leaves your device.

How to use

Open the calculator — no login, no installation required.
Enter your date of birth in the date picker field.
Click Calculate (or press Enter) — results appear instantly.
Read your 만 나이 (legal age), 세는나이 (traditional), and 연나이 (year-based) all at once.
Note the countdown to your next birthday shown under 만 나이.

FAQ

Is this calculator free to use?: Yes, completely free — no account, no subscription, and no usage limits.
Is my birth date uploaded to a server?: No. All calculations happen locally in your browser. Your date of birth is never sent to any server.
Does it work offline?: Yes. Once the page is loaded, it works with no internet connection — useful when traveling or in restricted networks.
What is the difference between 만 나이 and 세는나이?: 만 나이 counts completed years from birth (the international standard, now Korea's legal age since June 2023). 세는나이 starts at 1 at birth and adds 1 every January 1st regardless of birthday, so it can be 1-2 years higher.
What is 연나이 and when is it used?: 연나이 is simply the current year minus your birth year — no birthday check. It is used in some Korean laws and educational contexts such as school grade placement.
Which age do Korean offices and hospitals use now?: Since the age-counting law took effect on 28 June 2023, 만 나이 - the international count - is the default in laws, contracts and administrative paperwork unless a specific statute says otherwise. Two well-known exceptions still run on 연나이: school entry year and military conscription screening. That is why this tool shows all three numbers side by side rather than picking one for you.
Why does my Korean age jump on New Year's Day but my international age does not?: 세는나이 counts you as one at birth and adds a year every 1 January, so everyone ages together no matter when their birthday falls. 만 나이 only increases on the birthday itself. That is why the gap between the two numbers is two years before your birthday in a given year and one year after it.