Korean Lunar-Solar Calendar Converter — Leap Months and Ganji (Sexagenary Cycle)

Date & Time

A Korean lunar-solar converter changes dates between the Korean lunisolar calendar and the Gregorian calendar, showing leap-month status and the ganji (sexagenary cycle) names.

Lunar-Solar Converter

Runs in this browserKASI1000–2050

Converted with KASI-based data tables (korean-lunar-calendar). Supported range: lunar 1000-01-01 to 2050-11-18, solar 1000-02-13 to 2050-12-31. Conversion runs in your browser and input is never sent anywhere.

Direction

Solar date

Converted date

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What is it

The Korean lunar calendar is a lunisolar calendar based on moon phases, inserting a leap (intercalary) month roughly every two to three years to stay aligned with the seasons. This tool converts with the korean-lunar-calendar library, whose data tables follow Korea Astronomy and Space Science Institute (KASI) records, supporting lunar dates from 1000-01-01 to 2050-11-18 and solar dates from 1000-02-13 to 2050-12-31. Lunar input can be flagged as a leap month, and results include the year, month, and day ganji (for example byeong-o year) plus the Gregorian weekday. All conversion happens in your browser.

conversion = cumulative day count from the epoch (lunar 1000-01-01 = solar 1000-02-13) mapped through KASI-based lunar month length and leap-month tables

How to use

1Choose the direction: solar to lunar or lunar to solar.
2Enter the date, and for lunar input mark whether the month is a leap month.
3Press convert to see the converted date with leap-month status and ganji names.

Reference

Korean Lunar-Solar Calendar Converter — Leap Months and Ganji (Sexagenary Cycle) Reference
Lunar	Solar	Year ganji
2026-01-01 (Seollal)	2026-02-17 (Tue)	byeong-o (丙午)
2026-08-15 (Chuseok)	2026-09-25 (Fri)	byeong-o (丙午)
2025-06-01 (leap month)	2025-07-25 (Fri)	eul-sa (乙巳)

Sources & standards

음양력 변환 계산 (Lunar-Solar Conversion) - 한국천문연구원 (KASI)
korean-lunar-calendar — KASI-based conversion table library - usingsky (MIT License)

FAQ

What date range does the converter support?

Lunar dates from January 1, 1000 to November 18, 2050, and solar dates from February 13, 1000 to December 31, 2050. Dates outside this range are rejected.

How do leap months work?

Turn on the leap month toggle in lunar-to-solar mode to treat the entered month as intercalary. For example 2025 has a leap 6th month, so lunar leap 6/1 converts to July 25, 2025. If the year has no such leap month, the tool shows an error.

Is lunar converter input sent to a server?

No. Conversion uses data tables bundled in your browser and the entered date is never sent to a server.