The lunisolar calendar has 12 months totaling ~354 days, which drifts ~11 days per solar year. To realign, an extra (leap) month is inserted roughly every 2-3 years — about 7 times every 19 years. The leap month is named after the month it follows (윤4월 = 'leap April'). Only one specific year-month pair can be leap.

Why limit to 1900-2099?

Lunar calendar dates aren't derivable from a simple formula — they require astronomical observations of the new moon. Standard tables exist for 1900-2100 (Korea Astronomy and Space Science Institute publishes the official one). Beyond this range, dates are predictions that may differ slightly from official almanacs when published.

Lunar Calendar Converter

Time

The Korean/Chinese/Vietnamese lunisolar calendar is still used for traditional holidays, birthdays, and ancestral rites — Chuseok, Lunar New Year, Buddha's birthday all follow it. This converter handles both directions using the standard precomputed table of month lengths and leap month positions from 1900 to 2099 (the entire range modern Korean and Chinese references provide). It also outputs the zodiac animal of the lunar year and the ganzhi (heavenly-stem/earthly-branch) pair — `2024 갑진(甲辰)` means Wood Dragon. Leap months (윤달) are handled correctly with a checkbox for the rare lunar→solar direction.

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DirectionSolar (Gregorian) date

Result

2026.04.25

Zodiac animal

Horse

Ganzhi (heavenly-stem + earthly-branch)

丙午

Based on the standard Korean/Chinese lunisolar table. Range: 1900-01-31 to 2099-12-30.

How to use

Solar → Lunar: pick any Gregorian date from 1900-01-31 to 2099-12-31 to see the lunar equivalent.
Lunar → Solar: enter year, month, day. Check the leap month box only if the lunar month was a duplicated (leap) month that year.
The zodiac and ganzhi outputs help with traditional age calculation (만 나이 / 한국 나이 / 띠).

Frequently asked questions

What's a leap month?: The lunisolar calendar has 12 months totaling ~354 days, which drifts ~11 days per solar year. To realign, an extra (leap) month is inserted roughly every 2-3 years — about 7 times every 19 years. The leap month is named after the month it follows (윤4월 = 'leap April'). Only one specific year-month pair can be leap.
Why limit to 1900-2099?: Lunar calendar dates aren't derivable from a simple formula — they require astronomical observations of the new moon. Standard tables exist for 1900-2100 (Korea Astronomy and Space Science Institute publishes the official one). Beyond this range, dates are predictions that may differ slightly from official almanacs when published.