Free Chinese Lunar Calendar Converter

Worked example

Leave "Conversion direction" on "Gregorian → Lunar" and enter 29 January 2025 in "Gregorian date". The card shows 正月初一, "Lunar Year 2025 (乙巳 Yǐsì)", "Snake 蛇 (Snake)" and the weekday, Wednesday. Change the date to 28 January 2025 and it reads 腊月廿九 and "Lunar Year 2024 (甲辰 Jiǎchén)", because the day before the New Year still belongs to the old year. Enter 25 July 2025 and the card shows 闰六月初一 with the note "This date falls in the leap month that follows 六月 — shown as a repeated month in the lunar calendar." Now press "Lunar → Gregorian", set Year 2025, Month "6. 六月" and Day 1, and tick "This is the leap 六月 (闰月)". The answer is 2025-07-25. Without the tick it is 2025-06-25.

Which settings to use, and the limits

• Read the lunar year, not the Gregorian one. The card names the lunar year, which starts at the lunar New Year (正月初一), not on 1 January. A date in January or early February can therefore belong to the previous lunar year: 2025-01-28 is "Lunar Year 2024" (Dragon) and 2025-01-29 is "Lunar Year 2025" (Snake). The stem-branch name and the zodiac animal follow the lunar year. In 2026 the New Year falls on 2026-02-17. The banner at the top, "Today", shows today's lunar date and zodiac.
• Learn how the month and day names are written. Months are 正月 (1), 二月 to 十月, 冬月 (11) and 腊月 (12), and the "Month" menu shows them as "1. 正月" to "12. 腊月". Days run 初一 to 初十, 十一 to 十九, 二十, 廿一 to 廿九 and 三十. A leap month has 闰 in front, as in 闰六月. A lunar month has 29 or 30 days, so the "Day" box accepts 1 to 30 but each month is checked against its real length.
• Tick the leap-month box only for the leap month. A leap month repeats a month number after the regular one. The checkbox below the Day, Month and Year boxes reads "This is the leap 六月 (闰月)" for 2025, which has a leap month 6, and "This lunar year has no leap month" (greyed out) for a year without one, such as 2024 or 2026. In 2025 the regular month 6 runs 2025-06-25 to 2025-07-24 and the leap month starts on 2025-07-25 with 29 days. Other leap years include 2020 (month 4) and 2023 (month 2).
• Know the range, and that it is a stored table. The tool covers lunar years 1900 to 2100: Gregorian dates from 1900-01-31 to 2101-01-28, the last day of lunar year 2100. It reads a stored table of month lengths and leap months for those years rather than working out moon phases in your browser. It converts whole calendar dates only, with no time of day and no time zone. For an official document, check the date against a printed almanac or the issuing office.
• Copy the form you need. In "Gregorian → Lunar", "Copy" gives text such as "正月初一 Lunar Year 2025 (乙巳年)". In "Lunar → Gregorian", "Copy" gives the Gregorian date as year-month-day, such as 2025-07-25. After a click the button reads "Copied!" for a moment. Both result cards also show the weekday, written in the language of the page.
• Share a conversion as a link. "Share result" makes a link that reopens the same direction and date. A Gregorian date is carried as g=2025-01-29. A lunar date carries the year, month and day, plus lp=1 when the leap box is ticked. On a phone the button opens the share sheet, and on a computer it copies the link. The date sits after the # in the address, which browsers do not send to the server, and the conversion itself happens in your browser.

Common problems and how to fix them

It says "This date is outside the supported range (1900-01-31 to around 2100)."

The Gregorian date is before 1900-01-31, or after 2101-01-28, where the stored table ends. Choose a date inside that span. For lunar dates in the same years, use "Lunar → Gregorian" with a year from 1900 to 2100.

It says "Enter a valid Gregorian date."

The box holds something that is not a real date written as year-month-day. If your browser shows a plain text box instead of a date picker, type 2025-01-29, and avoid dates that do not exist, such as 2025-02-30. If you have filled only part of a date picker, no message and no result appear until the day, month and year are all set.

It says "Enter a lunar year between 1900 and 2100."

The "Year" box in "Lunar → Gregorian" is empty, is a decimal, or is outside 1900 to 2100. Type a whole lunar year in that span. Remember that this box takes the lunar year, so a date in January 2025 before the New Year belongs to lunar year 2024.

It says "This lunar year has no leap month on that number — uncheck the leap-month box."

The leap-month box is ticked, but the chosen month is not this year's leap month. In 2025 only month 6 has a leap twin, so set Month to 6 or untick the box. The tick stays when you change Month, or when you change Year to another year with a leap month, such as 2023 (month 2). Changing Year to one without a leap month, such as 2026, clears the tick.

It says "That day doesn't exist in this lunar month."

Lunar months have 29 or 30 days and the tool checks the real length for that year. In 2025, month 2 has 29 days, so day 30 fails, and the leap month 6 has 29 days. Lower the day to 29, or check whether the month is the right one. An empty Day box also gives this message.

How it compares

This converter does one lookup at a time between the Gregorian and Chinese lunar calendars, using a stored table for lunar years 1900 to 2100. It suits birthdays, festival dates and forms that quote a lunar date, and it shows the stem-branch year and the zodiac animal. It does not list solar terms, auspicious days, double-hour names or festivals, it does not draw a month grid, and it takes no time of day. A phone or desktop calendar with a Chinese calendar overlay shows a whole month beside your events, which is better for planning. For dates outside 1900 to 2100, or for official records, use a printed almanac or the issuing office.