Age Calculator

🎂 Age Calculator

Date of Birth

Gender (for life expectancy)

👨 Male

👆 Enter your date of birth above

🪖 Military Discharge Date

Based on 2024 mandatory service periods

Enlistment Date

Military Branch

Army / Marine (18 months)

👆 Enter your enlistment date above

Age Calculator · Korean Counting Age · Discharge · Life Progress

JAY Project's Age Calculator turns a single date of birth into your legal (international) age, Korean counting age, days until your next birthday, Korean military discharge date (Army/Navy/Air Force), and a life-expectancy-based progress bar — all visualised on one screen.

No sign-up required; the date is processed in your browser and never sent to a server.

The Korean age systems

Since June 2023 all Korean administrative, judicial, and public documents use the international (legal) age. The two older systems still appear in everyday speech, so it helps to know all three:

Legal age (만 나이): International standard — adds 1 on each birthday.
Korean counting age (세는 나이): Starts at 1 the day you're born; everyone gains a year on January 1.
Year age (연 나이): Current year − birth year (birthday-agnostic). Used in some Korean laws like the Youth Protection Act and military law.

Best Use Cases

🎂 Next-birthday countdown

See exactly how many days, hours, and minutes until your (or a friend's) next birthday.

🪖 Korean military discharge

Enter your enlistment date and branch (Army 18mo, Navy 20mo, Air Force 21mo) for an automatic discharge date and service-progress percentage.

⏳ Life-progress bar

Your current age plotted on the Korean average life expectancy (~83 years) — a visceral nudge for life planning or bucket lists.

How to Use

Enter your birth date: YYYY-MM-DD format.
See your ages: Legal age, Korean counting age, and a next-birthday D-Day appear instantly.
(Optional) Add enlistment date: Currently serving? Add the date and branch for the discharge countdown.
View life-progress bar: See your position on the life-expectancy timeline at a glance.

Frequently Asked Questions

Q. What is the Korean "manage" (legal) age?

Since June 2023 all Korean administrative, judicial, and public documents use the international age system: (current year − birth year) if your birthday has passed this year, otherwise (current year − birth year − 1). This calculator applies it automatically.

Q. How is Korean counting age different from international age?

Korean counting age starts at 1 on the day you are born and adds 1 every January 1st. International (legal) age starts at 0 and adds 1 on each birthday. The two can differ by 1-2 years for the same person.

Q. How is the Korean military discharge date calculated?

Enter your enlistment date and the calculator returns the discharge date based on standard service lengths: Army & Marines 18 months, Navy 20 months, Air Force 21 months. Days remaining and a service-progress percentage are shown alongside.

Q. What does the life-progress percentage mean?

It plots your current age against Korean average life expectancy (~83 years). The progress bar gives a visceral sense of remaining time — useful for life planning or motivation.

Q. Does it count down to my next birthday?

Yes — days, hours, and minutes until your next birthday appear as a D-Day countdown alongside your age.

Q. Can non-Koreans use this calculator?

Legal age, next-birthday countdown, and the life-progress bar work for anyone. The military discharge calculation is Korean-specific and shouldn't be used for other countries' service.

* All ages follow standard rules but specific legal interpretations may vary by statute. For binding legal effect, consult the relevant authority.
* Your date of birth is processed in your browser and never sent to a server.

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