Lunar Calendar Converter
Convert Gregorian dates to the Chinese lunar calendar and back, with zodiac animals, heavenly stems and leap months, from 1900 to 2100, fully offline.
How to use
- The default direction is Gregorian to lunar. Pick a date and the lunar wording, stems-branch year and zodiac appear at once.
- Press the today chip to see today's lunar date, handy for birthdays and anniversaries.
- Switch to Lunar to Gregorian, choose the lunar year, month and day, and the leap month shows up in the list when the year has one.
- If the range warning appears, the lunar date likely does not exist, such as a leap month picked for the wrong year.
- The stems-branch year follows the folk custom and switches on lunar new year, not on the solar term Beginning of Spring.
FAQ
Which dates are supported?
What is a leap month?
When does the stems-branch year change?
Does it need the network?
How to use
- Pick the direction
Gregorian to lunar is the default, and the chip switches it to lunar to Gregorian. Both directions share one calendar table, so results always agree.
- Enter the Gregorian date
Choose or type a date and the lunar wording, stems-branch year and zodiac appear instantly, with a today chip for one-tap checks.
- Enter the lunar date
In the reverse direction pick the lunar year, month and day. The month list adds a leap entry only when the year has one, and days list valid lengths only.
- Read the result
The result box shows the full wording with the weekday. Leap months carry an explicit marker, and the stems-branch year follows the folk new year convention.
About this tool
This converter serves anyone who needs lunar dates: finding a relative's lunar birthday, checking when a festival lands, or picking a day for a traditional event. Enter a Gregorian date and the page returns the lunar month and day in Chinese wording, the heavenly stems and earthly branch year, and the zodiac animal, with leap months clearly marked. The reverse direction works the same way, turning a lunar date back into the Gregorian calendar with its weekday.
The tool embeds a calendar bit table for 1900 through 2100 and computes everything locally, with no network calls and no uploaded input. The algorithm is verified against several anchors, for example 10 February 2024 maps to the first day of the first lunar month in the Jia-Chen year, and 22 March 2023 maps to the first day of the leap second month in the Gui-Mao year, with round trips staying consistent. Out of range inputs get a clear warning rather than a forced answer.
How it works
The lunar calendar fixes months by moon phase, starting each month on the new moon, so months last twenty nine or thirty days. Twelve lunar months fall about eleven days short of a solar year, so leap months are inserted seven times every nineteen years to stay in step with the seasons. Which month becomes leap depends on the twenty four solar terms: the month without a major term repeats the previous number with a leap marker. The embedded bit table packs each year's month lengths and leap data into one hex value.
The stems-branch year pairs ten heavenly stems with twelve earthly branches in order, completing a cycle every sixty years. The zodiac follows the branch, rat for zi, ox for chou, and so on. Note that two conventions exist for switching the year: folk custom uses lunar new year day, while ba zi charts switch at the Beginning of Spring solar term, which can differ by weeks. This page uses the folk convention, matching zodiac and festival habits, so use a dedicated chart tool for astrological work.
When to use it
- Finding a lunar birthday
For an elder whose birthday follows the lunar calendar, convert their birth date once, note the lunar month and day, then celebrate on the matching Gregorian day each year. Lunar birthdays stay fixed while Gregorian dates drift, so this mapping is the reliable way to remember and set reminders.
- Checking festival dates
Spring Festival, Dragon Boat, Qixi and Mid Autumn all follow the lunar calendar. To learn which Gregorian day Mid Autumn falls on in a given year, pick the eighth month day fifteen in the reverse direction. The answer is exact and ready for holiday planning.
- Picking dates with elders
When elders prefer traditional calendar choices for certificates or shop openings, batch convert the candidate dates, read out the months, leap markers and stems-branch years, and hand the list over. It saves paging through almanacs and avoids misreading leap years.
Tips & tricks
- When checking elders' birthdays, remember dates before 1949 are supported as well.
- The stems-branch year switches on lunar new year here; for ba zi charts use a tool with the Beginning of Spring convention.
- Before reversing a leap month date, confirm the year actually has one, such as the leap second month of 2023.
- Convert family lunar birthdays to Gregorian once and store them in your calendar app for good.
Things to watch
- Mixing the two year conventions
Switching stems at lunar new year and switching at Beginning of Spring are different customs, and near the boundary the zodiac or year pillar will disagree. This page uses the folk convention; ba zi work needs the solar term convention, so mixing them mislabels the animal or pillar.
- Treating leap months as normal
A leap month repeats the previous month and exists only in some years. Reading the leap second month as the third month, or hunting for a leap month in a year without one, produces wrong dates, so watch for the leap marker in the picker.
- Ignoring the supported range
Dates before 1900 or after 2100 fall outside the embedded table and the tool reports a clear error. When that happens for historical research or far future planning, the date is simply out of range, and forcing a guess would be wrong.