Lunar Age Calculator
세는나이 · 연 나이 · 만 나이

Korean Lunar Age
Calculator

Enter a solar or lunar birth date and get all three Korean ages at once, plus your zodiac animal and your real lunar birthday.

Our korean lunar age calculator converts 음력 birth dates to 양력 and works out your Korean age (세는나이), your year age (연 나이) and your international age (만 나이) — the legal standard since June 2023. Free, instant, and accurate for every year from 1900 to 2100.

Korean Lunar Age Calculator

Enter your birth date on either the solar (양력) or lunar (음력) calendar to get your Korean age, year age, and international age.

Enter your birth date

Korean lunisolar calendar · 1900–2100 · Zodiac turns over at Seollal

Quick Answer

How Korean Age Is Calculated

Three formulas, three answers. All of them are correct in Korea — they are just used in different places.

세는나이

Korean Age

You are 1 the day you are born and everyone gains a year on 1 January. This is the number Koreans use in conversation.

year − birth year + 1
연 나이

Year Age

Your birthday is ignored — only the year counts. Used for conscription, school entry, alcohol and tobacco.

year − birth year
만 나이

International Age

Starts at 0 and increases on your birthday. The legal default across South Korea since 28 June 2023.

completed years lived

What Is a Korean Lunar Age Calculator?

A korean lunar age calculator does two jobs at once. First it translates your birth date between the solar calendar (양력, yangnyeok) and the Korean lunar calendar (음력, eumnyeok). Then it applies the three different Korean age formulas to that date so you can see your Korean age, your year age, and your international age side by side.

Both halves matter. Korea kept lunar birthdays in family registers for generations, so millions of people have a birth date written in a calendar that drifts about eleven days against the Gregorian one every year. And Korea uses three parallel age systems in daily life, law and paperwork. Getting your Korean lunar age right means resolving both the calendar and the counting rule.

The calendar problem

A lunar date such as 음력 3월 15일 lands on a different Gregorian day every single year. If your grandmother's birthday is recorded lunar, you cannot simply write 15 March in your phone calendar — you need a fresh conversion each year. This tool computes it for the current year and for your next birthday.

The counting problem

Korea runs 세는나이, 연 나이 and 만 나이 in parallel. The same person can honestly be 30, 29 and 28 on the same afternoon depending on who is asking. A korean age calculator that returns only one number hides the two you probably needed.

The Three Korean Age Systems Explained

System 1

세는나이

Korean counting age

You are 1 the day you are born. Everyone gains a year together on 1 January.

year − birth year + 1

Used in conversation, at work, and to decide who uses honorifics with whom.

System 2

연 나이

Calendar-year age

Your birthday is ignored entirely — only the year of birth counts.

year − birth year

Used by the Military Service Act, the Youth Protection Act, and school entry rules.

System 3

만 나이

International age

You start at 0 and gain a year on your actual birthday, exactly as in the West.

completed years since birth

The legal default in South Korea since 28 June 2023.

One person, three ages — a worked example

Take someone born on 15 September 1995. Check their age on 1 March 2026, before their birthday has come round:

System Calculation Result
세는나이 2026 − 1995 + 1 32
연 나이 2026 − 1995 31
만 나이 birthday not reached yet 30

Three valid answers on the same day. This is exactly the confusion the 2023 reform set out to reduce.

The 2023 Korean Age Law — What Actually Changed

28 June 2023 — 만 나이 통일법

Amendments to the Civil Act (민법) and the Framework Act on Administration (행정기본법) took effect, establishing that any age stated in a law, contract, permit or public document means 만 나이 unless that specific statute says otherwise. Overnight, a large part of the country became one or two years younger on paper.

What changed

  • Contracts, insurance policies and administrative documents now default to 만 나이.
  • Medicine dosage guidance, welfare eligibility and pension ages read as 만 나이.
  • Ambiguous wording in older documents is now interpreted as 만 나이 by default.

What did not change

  • Military conscription still uses 연 나이 under the Military Service Act.
  • Alcohol and tobacco access still uses 연 나이 under the Youth Protection Act.
  • Elementary school entry is still keyed to the calendar year of birth.
  • Everyday conversation still runs on 세는나이 — and probably will for a long time.

How the Korean Lunar Calendar Affects Your Age

A lunisolar calendar, not a pure lunar one

The Korean traditional calendar is lunisolar. Each month begins at a new moon and runs 29 or 30 days, tracking the 29.53-day synodic cycle. Twelve of those months come to roughly 354 days — eleven short of a solar year — so an extra thirteenth month, the leap month (윤달), is inserted about every three years to pull the calendar back into line with the seasons. South Korea's official lunar calendar is computed by the Korea Astronomy and Space Science Institute (KASI).

This is a completely different design from the Islamic Hijri calendar, which has no leap month at all and therefore drifts through the seasons. If you want a Hijri age instead, use our Islamic lunar age calculator.

29.53

Days per lunar month

The synodic month. Korean lunar months therefore alternate between 29 and 30 days.

~11

Days of annual drift

Your lunar birthday moves about 11 days earlier each Gregorian year, then jumps forward in a leap year.

19

Year Metonic cycle

After 19 years the lunar and solar calendars nearly realign, so your lunar birthday returns close to the same solar date.

The trap near Seollal

This is the single most common error in Korean lunar age arithmetic. A baby born on 5 February 2024 in the solar calendar was born on 음력 2023년 12월 26일 — because Seollal 2024 did not arrive until 10 February. Their solar birth year is 2024, but their lunar birth year is 2023.

Consequence for the zodiac

That child is a Rabbit (토끼띠), not a Dragon. The 띠 changes at Seollal, so any calculator that reads the Gregorian year returns the wrong animal for every birth in January and early February.

Consequence for the count

Modern 세는나이 uses the solar year, so they count from 2024. The older, purely traditional count rolled over at Seollal and would count from 2023 — a one-year difference. The calculator above reports both.

Leap month (윤달) birthdays

If you were born in 윤달, the same leap month may not appear again for decades — leap 4th month, for instance, recurs on no fixed schedule. Korean families settle this pragmatically: they celebrate in the regular month of the same number. Our calculator applies that convention and flags it in the result so you know a substitution was made. To inspect leap months directly, use the Gregorian lunar converter.

How to Use the Korean Lunar Age Calculator

1

Pick the calendar your birth date is written in

Choose Solar (양력) if your date comes from a passport, ID card or hospital record. Choose Lunar (음력) if it comes from a family register, an older 주민등록 entry, or a relative who always says 음력. Getting this wrong shifts your result by up to a month.

2

Enter the date, and tick 윤달 only if it applies

In lunar mode, type the year, month and day exactly as recorded. Tick the leap month box only when the record shows 윤 in front of the month number. Leave it unticked otherwise — most records are regular months.

3

Read all three ages, plus your celebration dates

You get 세는나이, 연 나이 and 만 나이 together, your birth date rendered in both calendars, your 띠, this year's lunar birthday in Gregorian terms, and the Korean legal milestones tied to your birth year. Change the reference date to check your age at any point in the past or future.

Korean Zodiac Years (띠) Reference Table

Each year listed below runs from that year's Seollal to the next. If you were born in January or early February, your 띠 belongs to the previous row — check the Seollal table underneath to be sure.

Animal Korean 띠 Name Lunar Years
Rat 쥐 쥐띠 1948, 1960, 1972, 1984, 1996, 2008, 2020
Ox 소 소띠 1949, 1961, 1973, 1985, 1997, 2009, 2021
Tiger 호랑이 호랑이띠 1950, 1962, 1974, 1986, 1998, 2010, 2022
Rabbit 토끼 토끼띠 1951, 1963, 1975, 1987, 1999, 2011, 2023
Dragon 용 용띠 1952, 1964, 1976, 1988, 2000, 2012, 2024
Snake 뱀 뱀띠 1953, 1965, 1977, 1989, 2001, 2013, 2025
Horse 말 말띠 1954, 1966, 1978, 1990, 2002, 2014, 2026
Sheep 양 양띠 1955, 1967, 1979, 1991, 2003, 2015, 2027
Monkey 원숭이 원숭이띠 1956, 1968, 1980, 1992, 2004, 2016, 2028
Rooster 닭 닭띠 1957, 1969, 1981, 1993, 2005, 2017, 2029
Dog 개 개띠 1958, 1970, 1982, 1994, 2006, 2018, 2030
Pig 돼지 돼지띠 1959, 1971, 1983, 1995, 2007, 2019, 2031

Seollal (설날) Dates and Zodiac Cut-Offs

Seollal is Korean Lunar New Year — the first day of the first lunar month. It always falls between 21 January and 20 February, and it is the boundary at which the zodiac animal and the traditional lunar-year count change over.

Year Seollal Date Zodiac Begins
2020 January 25, 2020 Rat 쥐띠
2021 February 12, 2021 Ox 소띠
2022 February 1, 2022 Tiger 호랑이띠
2023 January 22, 2023 Rabbit 토끼띠
2024 February 10, 2024 Dragon 용띠
2025 January 29, 2025 Snake 뱀띠
2026 February 17, 2026 Horse 말띠
2027 February 6, 2027 Sheep 양띠
2028 January 26, 2028 Monkey 원숭이띠
2029 February 13, 2029 Rooster 닭띠
2030 February 3, 2030 Dog 개띠

Dates follow the KASI-published Korean lunar calendar. The calculator above computes Seollal for any year from 1900 to 2100.

Why Korean Age Matters Socially

Korean age is not trivia — it decides how two people speak to each other. Korean has multiple speech levels, and the choice between 반말 and 존댓말 depends heavily on relative age. Asking 몇 살이세요? early in a conversation is not nosiness; it is a request for the information needed to speak politely.

Because 세는나이 groups everyone born in the same calendar year, people born in the same year are 동갑 — age peers who can drop formality with each other regardless of who was born in January and who in December. That shared-year grouping is one reason the counting system has proved so durable even after the legal change.

Age-linked celebrations

  • 백일 (baegil) — the 100th day of life, counted from the day of birth.
  • 돌 (dol) — the first birthday, historically the first real milestone a child was expected to reach.
  • 환갑 (hwangap) — the 60th birthday, marking one full turn of the 60-year sexagenary cycle of stems and branches.
  • 칠순 (chilsun) — the 70th, still widely celebrated with an extended family gathering.

Where each system shows up

  • 만 나이 — contracts, insurance, medical dosing, pensions, visas.
  • 연 나이 — conscription, alcohol and tobacco, school year cohorts.
  • 세는나이 — conversation, honorifics, 동갑 groupings, most K-pop profiles.

환갑 and the 60-year cycle

The traditional Korean calendar labels each year with one of ten heavenly stems and one of twelve earthly branches. The combination repeats every sixty years, so your 60th birthday returns you to the exact stem-branch label of your birth year. That is what 환갑 celebrates — a completed cycle. Because the cycle is tied to lunar years, it lines up with your lunar birth year rather than your Gregorian one, which is another practical reason to know your Korean lunar age.

Common Mistakes When Calculating Korean Lunar Age

Treating a lunar date as a solar date

Typing 음력 3월 15일 into a normal date field as 15 March produces an error of several weeks. Always convert first — that is what the Solar/Lunar toggle is for.

Reading the zodiac off the Gregorian year

Anyone born between 1 January and Seollal belongs to the previous animal. This affects roughly one in ten births, and most online calculators get it wrong.

Adding 1 to your international age and stopping

The gap is 2 years before your birthday and 1 year after. A single fixed offset is wrong for most of the year.

Assuming 만 나이 now applies to everything

Conscription, the Youth Protection Act and school entry were explicitly carved out of the 2023 reform and still run on 연 나이.

Ignoring the 윤달 flag

A leap-month birth date entered as a regular month lands roughly 29 days off. If the record shows 윤, tick the box.

Confusing Korean age with Chinese lunar age

Both start at 1, but the Chinese count is usually described as rolling over at Lunar New Year, while modern 세는나이 rolls over on 1 January. For the Chinese version see our lunar age calculator.

Korean Lunar Age Calculator — Frequently Asked Questions

What is a Korean lunar age calculator?

A Korean lunar age calculator converts a birth date between the solar (양력) and lunar (음력) Korean calendars and then returns every Korean age at once: 세는나이 (Korean counting age), 연 나이 (calendar-year age) and 만 나이 (international age). It also shows which Gregorian date your lunar birthday falls on this year, because a lunar birthday moves by roughly 11 days each year.

How do I calculate my Korean age?

The standard Korean age formula is: current year − birth year + 1. You are considered one year old on the day you are born, and everyone gains a year together on 1 January. So someone born in 1995 is 31 in Korean age during 2025, even in December.

Is Korean age still used after the 2023 law change?

Yes, socially. On 28 June 2023 South Korea amended the Civil Act and the Framework Act on Administration so that 만 나이 (international age) is the default in all laws, contracts and official documents unless a statute says otherwise. In everyday conversation, however, Koreans still ask and answer with 세는나이, which is why a calculator showing all three numbers is useful.

What is the difference between Korean age and international age?

Korean age (세는나이) starts at 1 and increases on 1 January, so it is one or two years higher than international age. International age (만 나이) starts at 0 and increases on your birthday. The gap is 2 years if your birthday has not yet arrived this year, and 1 year after your birthday has passed.

What is 연 나이 and why is it different again?

연 나이 is simply current year − birth year. It ignores your birthday entirely. Korean statutes that need a clean, uniform cut-off still use it — most notably the Military Service Act, the Youth Protection Act that governs alcohol and tobacco, and school entry rules.

How does the lunar calendar change my Korean age?

It does not change the counting rules, but it changes which date you enter and which date you celebrate. Many Koreans born before the 1990s had their birthday recorded on the lunar calendar. If your family record says 음력, you must convert it to the solar date before applying any age formula — otherwise you can be a full month off, and near Seollal you can be a whole year off.

What happens if I was born in a leap month (윤달)?

A leap month is an extra lunar month inserted roughly every three years. Because the same leap month rarely recurs, Korean families almost always celebrate a 윤달 birthday in the corresponding regular month. This calculator follows that customary practice and tells you when it has made that substitution.

Which year does my Korean zodiac animal (띠) come from?

From the lunar year, not the Gregorian year. The animal changes at Seollal (Lunar New Year), which falls between 21 January and 20 February. So a baby born on 5 February 2024 is still a Rabbit (토끼띠), because Seollal 2024 was 10 February. Most simple calculators get this wrong; this one derives the animal from the converted lunar year.

Why is my Korean age two years higher than my Western age?

Because 세는나이 gives you a year at birth and then adds another year on the first 1 January of your life. A baby born on 31 December is 1 year old that day and 2 years old the next day, even though they are only one day old in 만 나이.

Is the Korean lunar calendar the same as the Chinese lunar calendar?

They share the same lunisolar structure — months follow the 29.53-day synodic cycle and leap months keep the year aligned with the seasons. Korea (KASI) and China compute the calendar for their own standard meridians, so on rare occasions a month boundary can differ by one day. For birthday and age purposes the two agree in virtually every case.

Can I use this calculator for official Korean paperwork?

Use the 만 나이 figure for anything official, since that is the legal standard. This tool is an educational and planning aid; for legally binding matters such as immigration, pensions or conscription, confirm with the relevant Korean authority or your 주민센터.

How do North Korean and South Korean age counting compare?

Both Koreas historically used the same East Asian counting age. South Korea moved to 만 나이 as the legal default in June 2023. Everyday counting-age habits remain common across the peninsula and in the wider Korean diaspora.

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