What does this tool do
The Lunar / Gregorian Date Converter converts between the Vietnamese lunar calendar (âm lịch) and the Gregorian (solar) calendar. Enter a Gregorian date to get the lunar equivalent, or enter a lunar date to get the Gregorian date. Useful for traditional holidays (Tết), anniversaries, and cultural events. Uses the lunar-javascript library for calculations.
How to use it
- Choose direction — Gregorian → Lunar or Lunar → Gregorian.
- Enter date — For Gregorian: pick day, month, year. For Lunar: enter day, month, year, and leap month if applicable.
- View result — The converted date appears with traditional names (Heavenly Stems and Earthly Branches) for year, month, and day when available.
- Switch — Change direction and convert the other way.
How it works
The tool uses the lunar-javascript library for Vietnamese lunar calendar conversion. The lunar calendar is based on moon phases and has leap months in some years. Conversion is bidirectional: Gregorian dates are converted to lunar day/month/year, and lunar dates are converted to Gregorian. The library also returns traditional almanac names (Heavenly Stems and Earthly Branches, e.g. Giáp Thìn for year) for year, month, and day. The library's rules are followed for leap months and year boundaries. Accuracy is not independently verified by this project.
All computation runs entirely in your browser. No data is sent to any server.
Use cases & examples
- Tết — Find the Gregorian date of Vietnamese New Year.
- Annals — Convert birthdates or historical events.
- Planning — Schedule events by lunar dates.
- Cultural — Understand lunar calendar structure.
- Dual calendar — Keep track of both systems.
Example
- Gregorian 1 Jan 2024 → Lunar equivalent (date depends on that year's lunar calendar).
- Lunar 1/1 (Tết) → Gregorian date for Vietnamese New Year.
Limitations & known constraints
- Vietnamese lunar — Supports Vietnamese lunar calendar; other lunar systems (e.g. Chinese) may differ.
- Library dependency — Accuracy depends on lunar-javascript; not independently verified.
- Leap months — Some years have a leap month; ensure correct input for lunar→Gregorian.
- Range — Library may have a supported year range; outside range may fail.