Korean Age – Calculator And Explanation Of The System

Korean age was a unique way of counting age that makes people in South Korea 1–2 years older than their international age. It was based on the idea that you're already one year old at birth and gain another year every January 1st, regardless of your actual birthday.

While this system was once deeply rooted in Korean culture and language, South Korea officially switched to the international age system in 2023. Korean age is no longer used in daily life or legal documents, but it’s still helpful to understand how it worked, especially when learning Korean or exploring cultural traditions.

In this guide, we’ll walk you through what Korean age was, why it changed, and how to calculate your former Korean age using our easy formulas or calculator.

Do you want a downloadable guide for this topic? We have a free PDF resource for you here:

Get "Korean Age" Free PDF Guide Quick Summary

• ✅South Korea officially switched to the international age system in 2023.
• ✅Korean age made Koreans 1–2 years older by counting age from birth and every January 1st.
• ✅You can still calculate your former Korean age using simple formulas or a calculator.
• ✅Understanding Korean age helps with cultural context, social language, and honorifics.

Contents

• 1 What is the difference between Korean age and international age?
  • 1.1 International Age vs Korean Age
• 2 Korean Age Calculator
• 3 South Korea’s Age System Explained
• 4 What Was the Korean Age System?
• 5 Why Did South Korea Change the Age System?
• 6 Why is Korean Age Important?
• 7 Why Was the Korean Age System Different?
• 8 How to Calculate Your Korean Age (Before 2023)
  • 8.1 1. Use the "Korean Age +1 Formula"
  • 8.2 2. Use the "Korean Age Birthday Formula"
  • 8.3 3. Use the Korean Age Calculator
• 9 BTS Members Age
• 10 How to Say Your Age in Korean
• 11 What Age System Does Korea Use Now?
• 12 Legal Age in Korea
  • 12.1 What is the legal drinking age in Korea?
• 13 Military Conscription Age in Korea
• 14 When Do Koreans Celebrate Their Birthdays?
• 15 Wow, we are the same age!
• 16 Frequently Asked Questions (FAQs)
• 17 What to Learn Next
• 18 Wrap Up

What is the difference between Korean age and international age?

The difference between Korean age and international age is that Korean age starts at 1 at birth and increases by one every January 1. On the other hand, the international age starts at 0 and only increases on your birthday. This makes the Korean age typically one to two years older than the international age.

Example: If you were born in December 2000, by January 2001, you would already be 2 years old in Korean age, but only 1 month old in international age.

System	How it Works	Example (Born Dec 2000, checking Jan 2001)
Korean Age	Start at 1 at birth, +1 on Jan 1 each year	2 years old
International Age	Start at 0, +1 on your birthday each year	1 month old

International Age vs Korean Age

Let's compare the international age system and the Korean age system. 

You might be wondering, "How old is Jungkook?"

Jungkook is 27 years old in international age as of December 2025. He was born on September 1, 1997. Let's break down the comparison between his international and Korean age below.

• Jungkook's Age (International):
  • On January 1st, 2025, his international age is 27.
  • On September 1st, 2025, his international age is 28.
  • On January 1st, 2026, his international age is 28
• Jungkook's Age (Korean):
  • On January 1st, 2025, his Korean age is 29.
  • On September 1st, 2025, his Korean age is 29.
  • On January 1st, 2026, his Korean age is 30.

This comparison shows how age was calculated before Korea switched to the international age in 2023.

Korean Age Calculator

If you’re curious about what your Korean, you can use the formulas or the legacy Korean age calculator below. We also recommend you try the formulas we provide before using the Korean age calculator (more on that in a bit).

Enter your birth year below, and the Korean age calculator will show you your age in Korea.

Note: The Korean age system is no longer officially used in South Korea, but this calculator shows how it was traditionally calculated.

Enter Your Birth Year: Your Korean age is years old.

The calculator above will use the Korean age formula and automatically calculate your Korean age.

South Korea’s Age System Explained

South Korea has officially switched to the international age system, meaning most Koreans are now 1–2 years younger than before. In the traditional “Korean age” system, everyone is considered 1 year old at birth and gains another year every January 1st, regardless of their actual birthday. As of 2023, the international age system (age increases on your birthday) is now the legal and social standard.

Watch this video to learn more on what was changed:

What Changed:

• Korean Age (Old System): You’re 1 year old at birth, and everyone adds a year on January 1st.
• International Age (New System): You’re 0 at birth, and age increases on your actual birthday.

Why It Matters:

The shift simplifies things by removing confusion from having multiple age systems. While the international age was already used for legal and medical matters, the Korean age was still widely used socially. Now, the international method is the standard across all official documents and everyday use.

What Was the Korean Age System?

Before 2023, South Korea used a unique way of calculating age called the Korean age system, which typically made people 1 to 2 years older than their international age.

Here’s how it worked:

• You were considered 1 year old at birth, reflecting the time spent in the womb.
• Then, instead of aging on your birthday, everyone added a year on January 1st, regardless of when they were born.

For example, if you were born on September 1st, you would turn 2 years old (Korean age) just a few months later on January 1st of the following year, even though you'd still be less than a year old by international standards.

This method of age counting was deeply rooted in Korean culture and widely used in daily life, social interactions, and even introductions. South Korea was the only country that practiced it officially, and it often led to confusion, especially in legal documents, healthcare, and when interacting with the international community.

To reduce this confusion, South Korea officially discontinued the Korean age system in June 2023, adopting the international age system for all legal, administrative, and public uses.

Why Did South Korea Change the Age System?

Until June 2023, the Korean age system was still commonly used in daily life, even though the international age system was already used in legal and medical contexts. This created confusion and inconsistency in everything from contracts to social interactions.

To solve this, the South Korean government passed a law officially adopting the international age system across all sectors.

According to a government survey conducted in September 2022, a majority of South Koreans supported the change and planned to use international age even in casual, everyday conversations once the law took effect.

Yoo Sang-bum of the ruling People Power Party explained that this move would help reduce legal disputes and social misunderstandings caused by multiple age systems. It also cuts down on unnecessary socio-economic costs tied to inconsistencies in age-based policies.

Minister of Government Legislation Lee Wan Kyu led the implementation of the change, emphasizing that this reform would create a clear, unified system and minimize confusion moving forward.

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Why is Korean Age Important?

Age in Korea is very important in Korean culture. Far more important than it is in Europe or the USA. Even though the Korean age system was discontinued in 2023, age still plays a crucial role in Korean culture and language. Understanding how it was used helps you better grasp social dynamics in Korea.

Often, the first question that people ask is, "How old are you?" People's age is important not just for things like whether you are old enough to buy cigarettes and alcohol but for a whole variety of social interactions in Korea.

People use different languages when speaking to people of different ages. They expect people to act differently, with younger generation expected to pour drinks or older people expected to pay for things.

Even the way you refer to your friends is based on their age; if they are a year older than you, they might be your 누나 (nuna) or 언니 (eonni), if they are younger, they will be your 동생 (dongsaeng).

With all this importance on age, answering the question "How old are you?" is very important. But the answer depends on the meaning of the question.

Why Was the Korean Age System Different?

The Korean age system was different from the international system for two key reasons. First, you are automatically one year old at birth. Second, you age another year because of the turn of the calendar year. Your date of birth doesn't affect your Korean age.

In contrast, if you are a baby born in the USA, then you are considered to be one day old on the day after you are born. The nine months that you spent inside your mommy's tummy are not considered part of your age. Your age increases by one each time your date of birth passes.

In Korea, on the day of your birth, you are considered one year old; the time you spent in the womb counts as the first year of your life (despite it only being nine months). Because of this, your Korean age is always at least one year higher than your international age or Western age. Then, the change of the year on January 1st automatically advances a person's Korean age by one. You can read more about Korean months here.

Since June 2023, Korea has moved away from this system and now uses only the international age.

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How to Calculate Your Korean Age (Before 2023)

If you're asking yourself, "How old am I in Korean age?" there are three simple ways to get the answer. One of the easiest and simplest ways of knowing your age in South Korea is to add one year to the current year and then subtract your year of birth. This method will make you one year older than your Western age.

For example, if the current year is 2021 and the year you were born is 1992, you'll add one year to the current year (2021 + 1) and subtract your year of birth. This is (2021 + 1) - 1992 = 30.

Another method of knowing your age in Korea or using the Korean system is by adding one year to your Western age if your birthday has passed upon age calculation, and adding two years if your birthday hasn't passed yet. And lastly, use the Korean age calculator.

Pick whichever one you like best among these. We recommend using this calculator last. Let's take a look at the examples of each method below.

1. Use the "Korean Age +1 Formula"

(Current year – Year of Birth) + 1 = Korean Age

If you were born in 1995 and the year is 2019:

(2019 - 1995) + 1 = 25 years old (Korean age)

2. Use the "Korean Age Birthday Formula"

Birthday has passed this year: Your Age + 1 = Korean Age

Birthday has not passed this year: Your Age + 2 = Korean Age

If you are 25 and your birthday has passed:

25 + 1 = 26 years old (Korean age)

If you are 25 and your birthday has not passed this year:

25 + 2 = 27 years old (Korean age)

This means that your Korean age will be one or two years more than your Western age.

3. Use the Korean Age Calculator

Using the online Korean Age Calculator is super easy; just input your birth year. We recommend using the formulas above first and then checking your answer by using the Korean age calculator afterward.

Enter Your Birth Year: Your Korean age is years old.

If you want to get a solid understanding of age in Korea, then you could try to calculate Korean age using formulas, like those of celebrities or people you know. Then, you can use the online Korean age calculator to check if you're correct.

Keep in mind that the Korean age calculator uses today's date. If you want to calculate a Korean age on a different date, use formulas 1 and 2.

BTS Members Age

If you have already familiarized yourself with how to determine your Korean age from the example above, then a bit more practice won't hurt! Here are the birthdays of the rest of the BTS members that you can use to practice knowing someone's Korean age.

• Kim Namjoon - September 12, 1994
• Min Yoongi - March 9, 1993
• Jung Hoseok - February 18, 1994
• Kim Taehyung - December 30, 1995
• Park Jimin - October 13, 1995
• Kim Seokjin - December 4, 1992

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How to Say Your Age in Korean

Knowing how to say your Korean age in the Korean language is really useful when learning how to speak Korean. It's for sure to come up in conversation. You can say your Korean age by using this sentence. The online age calculator and formulas above will help you get the correct Korean age to use.

Since 2023, people have now referred to their international age when saying how old they are in Korean.

Example:

저는 스무 살입니다 (jeoneun seumu sarimnida).

This means "I am 20 years old". You can substitute your age by using the chart below. If you don't know how Korean numbers work, then check out this resource.

Korean	Romanization	English
한 살	han sal	1 year old
두 살	du sal	2 years old
세 살	se sal	3 years old
네 살	ne sal	4 years old
다섯 살	daseot sal	5 years old
여섯 살	yeoseot sal	6 years old
일곱 살	ilgop sal	7 years old
여덟 살	yeodeol sal	8 years old
아홉 살	ahop sal	9 years old
열 살	yeol sal	10 years old
열한 살	yeolhan sal	11 years old
열두 살	yeoldu sal	12 years old
열세 살	yeolse sal	13 years old
열네 살	yeolle sal	14 years old
열다섯 살	yeoldaseot sal	15 years old
열여섯 살	yeollyeoseot sal	16 years old
열일곱 살	yeorilgop sal	17 years old
열여덟 살	yeollyeodeol sal	18 years old
열아홉 살	yeorahop sal	19 years old
스무 살	seumu sal	20 years old
스물한 살	seumulhan sal	21 years old
스물두 살	seumuldu sal	22 years old
스물세 살	seumulse sal	23 years old
스물네 살	seumulle sal	24 years old
스물다섯 살	seumuldaseot sal	25 years old
스물여섯 살	seumullyeoseot sal	26 years old
스물일곱 살	seumurilgop sal	27 years old
스물여덟 살	seumullyeodeol sal	28 years old
스물아홉 살	seumurahop sal	29 years old
서른 살	seoreun sal	30 years old
서른한 살	seoreunhan sal	31 years old
서른두 살	seoreundu sal	32 years old
서른세 살	seoreunse sal	33 years old
서른네 살	seoreunne sal	34 years old
서른다섯 살	seoreundaseot sal	35 years old
서른여섯 살	seoreunyeoseot sal	36 years old
서른일곱 살	seoreunilgop sal	37 years old
서른여덟 살	seoreunyeodeol sal	38 years old
서른아홉 살	seoreunahop sal	39 years old
마흔 살	maheun sal	40 years old
마흔한 살	maheunhan sal	41 years old
마흔두 살	maheundu sal	42 years old
마흔세 살	maheunse sal	43 years old
마흔네 살	maheunne sal	44 years old
마흔다섯 살	maheundaseot sal	45 years old
마흔여섯 살	maheunyeoseot sal	46 years old
마흔일곱 살	maheunilgop sal	47 years old
마흔여덟 살	maheunyeodeol sal	48 years old
마흔아홉 살	maheunahop sal	49 years old
쉰 살	swin sal	50 years old
쉰한 살	swinhan sal	51 years old
쉰두 살	swindu sal	52 years old
쉰세 살	swinse sal	53 years old
쉰네 살	swinne sal	54 years old
쉰다섯 살	swindaseot sal	55 years old
쉰여섯 살	swinyeoseot sal	56 years old
쉰일곱 살	swinilgop sal	57 years old
쉰여덟 살	swinyeodeol sal	58 years old
쉰아홉 살	swinahop sal	59 years old
예순 살	yesun sal	60 years old
예순한 살	yesunhan sal	61 years old
예순두 살	yesundu sal	62 years old
예순세 살	yesunse sal	63 years old
예순네 살	yesunne sal	64 years old
예순다섯 살	yesundaseot sal	65 years old
예순여섯 살	yesunyeoseot sal	66 years old
예순일곱 살	yesunilgop sal	67 years old
예순여덟 살	yesunyeodeol sal	68 years old
예순아홉 살	yesunahop sal	69 years old
일흔 살	ilheun sal	70 years old
일흔한 살	ilheunhan sal	71 years old
일흔두 살	ilheundu sal	72 years old
일흔세 살	ilheunse sal	73 years old
일흔네 살	ilheunne sal	74 years old
일흔다섯 살	ilheundaseot sal	75 years old
일흔여섯 살	ilheunyeoseot sal	76 years old
일흔일곱 살	ilheunilgop sal	77 years old
일흔여덟 살	ilheunyeodeol sal	78 years old
일흔아홉 살	ilheunahop sal	79 years old
여든 살	yeodeun sal	80 years old
여든한 살	yeodeunhan sal	81 years old
여든두 살	yeodeundu sal	82 years old
여든세 살	yeodeunse sal	83 years old
여든네 살	yeodeunne sal	84 years old
여든다섯 살	yeodeundaseot sal	85 years old
여든여섯 살	yeodeunyeoseot sal	86 years old
여든일곱 살	yeodeunilgop sal	87 years old
여든여덟 살	yeodeunyeodeol sal	88 years old
여든아홉 살	yeodeunahop sal	89 years old
아흔 살	aheun sal	90 years old
아흔한 살	aheunhan sal	91 years old
아흔두 살	aheundu sal	92 years old
아흔세 살	aheunse sal	93 years old
아흔네 살	aheunne sal	94 years old
아흔다섯 살	aheundaseot sal	95 years old
아흔여섯 살	aheunyeoseot sal	96 years old
아흔일곱 살	aheunilgop sal	97 years old
아흔여덟 살	aheunyeodeol sal	98 years old
아흔아홉 살	aheunahop sal	99 years old
백 살	baek sal	100 years old
백한 살	baekan sal	101 years old
백두 살	baekdu sal	102 years old
백세 살	baekse sal	103 years old
백네 살	baengne sal	104 years old
백다섯 살	baekdaseot sal	105 years old
백여섯 살	baengnyeoseot sal	106 years old
백일곱 살	baegilgop sal	107 years old
백여덟 살	baengnyeodeol sal	108 years old
백아홉 살	baegahop sal	109 years old
백열 살	baengnyeol sal	110 years old
백열한 살	baengnyeolhan sal	111 years old

What Age System Does Korea Use Now?

As of June 2023, South Korea officially uses only the international age system for all legal, administrative, and everyday purposes. The traditional Korean age system has been discontinued in all official settings.

Previously, international age was mainly used in legal and medical contexts, while Korean age was used socially. Now, the international system is the single standard used across the country.

Legal Age in Korea

With the switch to the international age in 2023, all age-based regulations in South Korea, including legal drinking, smoking, driving, and voting, are now determined based on your international age.

For most things, the minimum or legal age in South Korea is 19 years old (international age), which means you must have completed 18 full years.

What is the legal drinking age in Korea?

The legal drinking age in South Korea is now based on the international age. You must be at least 19 years old internationally to legally consume alcohol.

Establishments often perform ID checks to ensure compliance, especially in bars and convenience stores. While enforcement may vary, this age rule is now clearly defined by international standards.

Military Conscription Age in Korea

Mandatory military service is required for male South Korean citizens and is now determined by international age standards.

According to Korean law, all men between the ages of 18 and 28 (international age) must serve in the military, typically for around 18 to 21 months, depending on the branch. The shift to an international age simplifies the enlistment process and ensures consistency with other legal standards.

You can learn more about the military service in Korea here.

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When Do Koreans Celebrate Their Birthdays?

South Koreans celebrate their birthdays on the actual date they were born, just like in most other countries. The birthday celebration usually involves cake, food, and spending time with loved ones.

In the past, the traditional Korean age system made it seem like everyone “aged” together on January 1st, even though personal birthdays were still celebrated normally. That system has now been officially discontinued, and South Korea follows the international age system, where your age increases on your actual birthday.

Want to learn more about birthday traditions, vocabulary, and celebrations in Korea? Check out our full guide to birthdays in Korean.

Wow, we are the same age!

As age determines a complete host of social interactions in Korea, being of the same age can make everybody feel more comfortable.

If somebody that you have just met finds out that you are the same age as them, they will often be excited. This is because if you and your friend are the same age, neither person will have any of the social obligations that come from being a different age from the other. This concept still exists culturally, even though Korean age is no longer used officially.

Being the same age as another person has a special word in Korean: 동갑 (donggap). You will often hear the expression 우리는 동갑이다 (urineun donggabida), which means "we are the same age."

As the age system in Korea is based on the year of birth rather than your birthday, you will always be the same age as this new friend, even if your birthday is the very next day!

Frequently Asked Questions (FAQs)

Here are the commonly asked questions about the Korean age.

What is the Korean age rule?

As of June 2023, South Korea officially adopted the international age system. Now, a person’s age in Korea is the same as in most countries:

Age = Current year – Birth year (adjusted for whether the birthday has passed).

Previously, South Korea also used the “Korean age” system, where everyone was considered 1 year old at birth and everyone gained a year on January 1st, regardless of their actual birthday. This traditional system is no longer used in legal or official records, but it may still be used informally in everyday conversations or cultural contexts.

How old is 17 in Korean age?

Under the traditional Korean age system, someone who is 17 in international age would be considered either 18 or 19 in Korean age, depending on whether their birthday had already passed in that year.

Since June 2023, Korea has used international age in official contexts, so if someone says they are 17 in Korean age today, they are likely 16 or 17 in international age.

Is 18 still a minor in Korea?

Yes. Legal adulthood in South Korea begins at 19 years old under international age. An 18-year-old is still considered a minor under civil law. However, for some areas of law, such as criminal responsibility, the minimum age is lower (typically 14 and above). Therefore, while an 18-year-old may be subject to some legal responsibilities, they are not recognized as a full legal adult.

What is my Korean age if I'm 18?

If you are 18 in international age, under the traditional Korean age system, you would have been 19 if your birthday had already passed this year, or 20 if your birthday had not yet occurred. Since the adoption of the international system in June 2023, your official age in Korea is simply 18, the same as your international age.

What to Learn Next

If you liked this article and want to learn Korean, head over here for more great resources:

1. The how-to guide for learning the language: https://www.90daykorean.com/learn-korean/
2. Korean Phrase List: https://www.90daykorean.com/korean-phrases/
3. Korean Grammar Guide: https://www.90daykorean.com/korean-grammar/
4. Korean Sentence Structure: https://www.90daykorean.com/korean-sentence-structure/
5. Why Learn Korean?: https://www.90daykorean.com/why-learn-korean/

Wrap Up

Now you know the difference between Korean and international age, and how to calculate your former Korean age for fun or cultural context! Thanks to the 2023 update, most people in South Korea are now considered 1–2 years younger than before.

Other interesting questions that you might be asked when meeting new people are about your zodiac sign or blood type. Make sure to visit our articles about them, too, so you'd be prepared to answer them all!

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