Korean Lunar Birthday Calculator

What is the Korean lunar calendar (음력)?

Korea runs on two calendars at once. The solar (Gregorian) calendar — 양력 (yangnyeok) — handles everything official: school, work, contracts, your passport. But the traditional lunar calendar — 음력 (eumnyeok) — still governs the biggest holidays, ancestral rites, fortune-telling, and, for many families, birthdays.

The lunar calendar is technically a lunisolar calendar: each month begins on a new moon and lasts 29 or 30 days, and a normal year of 12 lunar months adds up to only about 354 days — roughly 11 days short of the solar year. Left alone, the calendar would drift backwards through the seasons, so every two or three years an extra leap month is inserted to pull it back in line. The result: any fixed lunar date, like your lunar birthday, lands on a different solar date every single year. That's exactly why you need a converter like the one above rather than simple mental math.

Solar birthday vs lunar birthday — a real generational divide

Ask a Korean friend when their grandmother's birthday is, and there's a good chance the answer is something like "the 3rd day of the 8th lunar month" — a date the family has to look up on the calendar each year. For older generations, celebrating the lunar birthday (음력 생일) is simply how it has always been done; birth dates were traditionally recorded on the lunar calendar, and many older Koreans' official documents even carry a lunar date written as if it were solar.

Younger Koreans, on the other hand, almost universally celebrate their solar birthday — the same fixed date every year, just like in the West. The practical result is a sweet little family ritual: every year, someone checks when 할머니 (grandma) and 할아버지 (grandpa) have their lunar birthday, and the family gathers on a date that may move by weeks from one year to the next. If you're dating a Korean, married into a Korean family, or just want to impress your in-laws — knowing (and remembering!) a lunar birthday is a genuinely appreciated gesture.

One related quirk: because many Koreans effectively have two birthdays, age can get fuzzy too. Korea historically used its own age-counting system on top of everything else — check yours with our Korean Age Calculator.

Seollal, Chuseok, and other lunar holidays

The two biggest holidays in Korea are both lunar dates, which is why they "move around" on the Western calendar:

• Seollal (설날) — Lunar New Year, the 1st day of the 1st lunar month. It falls anywhere between late January and mid-February (February 17 in 2026), and it's when the whole country travels home, eats 떡국 (rice-cake soup), and performs 세배, the New Year's bow to elders.
• Chuseok (추석) — the harvest festival on the 15th day of the 8th lunar month, always near a full moon in September or early October. Think of it as Korean Thanksgiving.
• Buddha's Birthday (부처님 오신 날) — the 8th day of the 4th lunar month, when temples across the country glow with lotus lanterns.

Fun tie-in: because the zodiac year officially turns over at the lunar new year, your Korean zodiac animal depends on your lunar birth year — not the solar one. If you were born in January or February, your animal may not be what you think. This calculator already shows it from your lunar year, and our Korean Zodiac Calculator gives you the full profile: Hangul name, personality, best matches, and your element-color year.

What is 윤달 — the leap month?

The leap month — 윤달 (yundal) — is the lunar calendar's balancing trick. To close that 11-day annual gap with the solar year, an entire extra month is inserted about seven times every 19 years. The leap month repeats the number of the month before it: 2025, for example, has a leap 6th month (윤6월), so that year runs 1월, 2월, … 6월, 윤6월, 7월 … for a total of 13 months and 384 days.

Being born in a 윤달 is genuinely rare — and it creates a birthday puzzle, because your exact leap month might not come around again for decades. The common solution: leap-month babies simply celebrate in the regular month of the same number each year, which is also what this calculator assumes. Culturally, 윤달 is considered a "spare" month outside the normal order of things — traditionally an auspicious window for tasks like preparing burial clothes or moving graves, since it was believed the spirits weren't watching the extra month.

How to wish someone a happy birthday in Korean

Once you know when the birthday is, you'll want to say something! Korean birthday wishes change with formality — and this matters, because lunar birthdays usually belong to elders:

• 생일 축하해요 (saengil chukahaeyo) — "Happy birthday," polite and friendly. Safe for friends, colleagues, and most adults.
• 생일 축하해 (saengil chukahae) — casual, for close friends and people younger than you.
• 생신 축하드려요 (saengsin chukadeuryeoyo) — the honorific version for grandparents, parents, and elders. Notice that even the word for "birthday" changes: 생신 (saengsin) is the respectful form of 생일 (saengil), and 드려요 makes the verb humble.

So for a grandmother's lunar birthday, the natural thing to say is 할머니, 생신 축하드려요! — "Grandma, happy birthday!" said with full respect. Korean dates themselves (7월 3일, "month 7, day 3") are read with Sino-Korean numbers — a different set from the native numbers used for age. If that sounds confusing, our guide to Korean numbers: Sino vs Native untangles the two systems once and for all.

Frequently asked questions

How do I find my lunar birthday?

Enter your solar (Gregorian) date of birth into the converter above. It looks up the traditional Korean lunisolar calendar tables for 1900–2050 and returns your birth date on the lunar calendar (음력) — for example, someone born on August 28, 1995 was born on lunar month 8, day 3. It also shows the solar date your lunar birthday falls on this year and next, since that date shifts every year.

Why is my lunar birthday on a different solar date every year?

A lunar month follows the Moon's phases and lasts about 29.5 days, so a 12-month lunar year is roughly 354 days — about 11 days shorter than the solar year. That gap makes every lunar date drift earlier against the Gregorian calendar each year, until a leap month is inserted and pushes it back. This is the same reason Seollal (Lunar New Year) lands anywhere between late January and mid-February.

What is a leap month (윤달) in the Korean lunar calendar?

A leap month (윤달, yundal) is an extra thirteenth month inserted roughly every two to three years to keep the lunar calendar aligned with the solar year and the seasons. It repeats the number of the month it follows — for example, 2025 has a leap 6th month (윤6월). People born during a leap month usually celebrate their birthday in the regular month of the same number, because their exact leap month only comes around every couple of decades.

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

Almost — both are lunisolar calendars built on the same astronomical rules, so their dates match nearly all the time. But Korea calculates its calendar from Korea Standard Time (UTC+9) while China uses Beijing time (UTC+8), and that one-hour difference occasionally shifts a new moon across midnight, making a Korean lunar month start one day earlier or later than the Chinese one. This tool follows the Korean convention, so dates like Seollal and Chuseok match the official Korean holiday calendar.