Chinese Lunar Calendar Converter

Two things in the table are worth pointing at. Every month is 29 or 30 days, never 31 and never 28, because a lunar month is one full cycle of the moon and that cycle is about 29 and a half days long. The calendar rounds alternately to keep up. To find one month in particular, read down the left column: the 1st lunar month opens the year at Chinese New Year, the 8th lunar month carries the Mid-Autumn Festival on its 15th day, and the 9th lunar month holds the Double Ninth. And neither year here repeats a month; the next one that does is 2028, which will carry a second 5th month.

One famous date is missing from the table on purpose. Qingming, the tomb-sweeping festival, has no lunar date at all. It is a solar term, fixed to the sun's position and landing on April 4 or 5 every year, which is why it barely moves while Chinese New Year swings across a month. It is the clearest reminder that this calendar has two engines in it, and that only one of them is the moon.

For any date outside these two years, the converter handles 1900 through 2100 in both directions. If what you actually want is the year's animal rather than the date, the Chinese zodiac hub carries the full year table, and the year-boundaries dataset covers the awkward January and February birthdays where two rules disagree.

Two other things on this site are really conversions in disguise. Your Chinese age is counted in lunar years, which is how a January baby can be two years old a fortnight after being born. And the Qing palace gender chart takes a lunar age and a lunar conception month as its two inputs, which is the real reason so many people arrive at a calendar converter looking for it. Both run on this same engine, so the numbers agree wherever you start. If you are chasing the folk methods rather than the chart, we checked fourteen old wives' tales against their earliest sources and any controlled study, and two of them survive.

The Chinese calendar is lunisolar, which is a polite way of saying it refuses to choose. Each month begins on a new moon and runs 29 or 30 days, so the 15th of any lunar month is always a full moon; that is why the Mid-Autumn Festival, the 15th day of the 8th lunar month, is always celebrated under one. But twelve moon-months add up to only about 354 days, eleven short of the solar year, and a calendar left to drift would soon put the "spring festival" in midwinter. The fix is elegant: every two or three years, one month is simply told to repeat itself.

That repeated month is the leap month, 闰月 (rùnyuè), and it is the gear that keeps the whole machine honest: seven leap months slot into every nineteen years, and the seasons stay put. Which month doubles is not a matter of taste. The calendar tracks the sun through twelve "major terms" spaced around the year, half of the 24 solar terms; a lunar month that fails to contain one is declared the leap month, a rule determined by astronomy rather than committee. In 2023 it produced a second 2nd lunar month; in 2025, a second 6th lunar month. There is no leap month at all in most years, which is exactly why the date of Chinese New Year swings between January 21 and February 21 and back again.

One consequence surprises nearly everyone: because the lunar year changes hands at Chinese New Year rather than on January 1, a January or February birthday often belongs to the previous lunar year, and with it the previous zodiac animal. Someone born on February 1, 1983 arrived before that year's new year (February 13) and is a Dog of 1982, not a Pig of 1983, whatever the horoscope placemats say. Our converter works this out from the real calendar, and tells you when it matters.

In many Chinese families a person simply has two birthdays: the Western one on documents and cake, and the lunar one, 农历生日 (nónglì shēngrì), the one a grandmother remembers without being told. Because the two calendars slide against each other, your lunar birthday lands on a different Western date every year, wandering across a window about a month wide. Traditional milestones ride on the lunar side: the red-egg celebration at one month old, the sixtieth birthday that closes a full cycle of the calendar, the ancestral offering dates kept in the lunar count.

The sixty-year cycle is the part most Westerners never hear about. Years are not only numbered, they are named: each carries one of ten "heavenly stems" (which give it an element) paired with one of twelve "earthly branches" (which give it an animal), and the pairing repeats only after sixty years. 2026 is a Fire Horse year, the 43rd name in the cycle; the same name last appeared in 1966 and returns in 2086. When our converter hands you a year, it hands you the full identity, the same one a fortune-teller would start from. That year-name is only the first of four: a bazi chart reads the same stem-and-branch pairing for your month, day and hour as well, and it is the day pair, not the year, that a reader treats as the center of the chart.

There is no formula that maps one calendar onto the other; the lunar calendar is defined by the actual sky. Modern Chinese calendars are computed from the true positions of the sun and moon, a standard set by China's national calendar specification (GB/T 33661-2017) and maintained by the Purple Mountain Observatory, the institution that has issued the official almanac since 1929. Our converter uses an astronomical implementation of the same rules across 1900–2100, not a rounded lookup table, and we cross-check output against the Hong Kong Observatory's published conversion tables. When a date can't exist (a 30th day of a 29-day month, a leap month in a year that had none) we say so plainly instead of guessing.