Lunar Age Calculator
Find your Chinese lunar age (虚岁) on any date, or a mother's lunar age and the lunar month at conception. Chinese New Year, leap months and time zones are handled. Nothing you enter leaves this device.
Mother's lunar age and lunar month at conception
The traditional Chinese gender chart is read with two values: the mother's lunar age when the baby was conceived, and the lunar month of conception. Enter the conception date, or the due date if that's all you know.
How lunar age works
Lunar age, or traditional Chinese age (虚岁, xūsuì), counts a baby as 1 at birth and adds a year for everyone at Chinese New Year, not on birthdays. The reliable way to work it out is to count Chinese years:
Lunar age = the current Chinese year − the Chinese year of birth + 1
Chinese years start at Chinese New Year, between January 21 and February 20. So the Chinese year of birth is the previous year for anyone born in January or February before that year's New Year.
| Born | On | Lunar age | Western age | Why |
|---|---|---|---|---|
| Feb 10, 1990 | Oct 1, 2026 | 37 | 36 | Born after Chinese New Year 1990 (Jan 27). 36 New Years since, plus 1 |
| Jan 20, 1990 | Oct 1, 2026 | 38 | 36 | Born before Chinese New Year 1990, so the Chinese year of birth is 1989. 37 New Years since, plus 1 |
| Oct 1, 2026 | Feb 6, 2027 | 2 | 0 | One at birth, two at the first Chinese New Year, four months later |
Two shortcuts that go wrong
- "Western age + 1" ignores Chinese New Year. Between the New Year and your birthday it is one too low: someone born on July 15, 1990 is 36 on March 1, 2027, so the shortcut gives 37, but their lunar age is 38.
- "Western age + 2 if Chinese New Year has passed, otherwise + 1" assumes your birthday hasn't come yet this year. Once it has, the shortcut is one too high: the same person on October 1, 2026 is 36, so it gives 38, but their lunar age is 37.
Born in January or February?
Chinese New Year 1990 fell on January 27. Someone born on January 20, 1990 belongs to the Chinese year 1989, and someone born three weeks later, on February 10, 1990, to 1990. On October 1, 2026 their lunar ages are 38 and 37, although both are 36 by Western age.
Some traditions, including BaZi and many almanacs, start the year at the Start of Spring (立春), around February 4, instead of Chinese New Year. If a birth falls between the two, the counts differ by one. The calculator shows both when that happens. The Chinese zodiac calculator works the same way for zodiac signs.
Born outside China?
The Chinese calendar is calculated for China Standard Time (UTC+8). For almost everyone this changes nothing, because the lunar year only turns at Chinese New Year. It matters for a birth on the evening before the New Year in the Americas or Europe, when it was already New Year's Day in China.
For example, a baby born at 8:00 pm on February 5, 2027 in New York was born at 9:00 am on February 6 in Beijing, which is Chinese New Year's Day. By the China date the baby belongs to the Chinese year 2027, and by the New York date to 2026, so the two counts differ by one for life. Open "Born outside China near Chinese New Year?" in the calculator and add the time and city to see both. Our method page explains how we handle time zones and historical daylight saving.
Lunar age for the Chinese gender chart
The Chinese gender chart, also called the Chinese birth chart, has a row for the mother's lunar age at conception and a column for each lunar month. Using her Western age or the Gregorian month puts many people in the wrong cell. Three things to check:
- Conception near Chinese New Year. Both values change together. For a mother born on March 15, 1994, a conception on February 16, 2026 gives lunar age 32 and the 12th month; two weeks later, on March 1, 2026, it gives 33 and the 1st month. Chinese New Year 2026 was February 17.
- Leap months. Some years have a 13th month that repeats a month number. 2025 had a leap 6th month, from July 25 to August 22, 2025, and 2028 will have a leap 5th month, from June 23 to July 21, 2028. Most people read a leap month as the month with the same number, though some count its second half as the next month.
- Only a due date? Conception is about 266 days (38 weeks) before the due date. That estimate can easily be a week or two out, so check whether it sits near the edge of a lunar month.
The chart is folklore with no scientific basis. A study of about 2.8 million births in Sweden from 1973 to 2006 found that it predicted the baby's sex correctly about half the time, no better than chance (Villamor and others, 2010). Enjoy it as a cultural tradition, not as a forecast.
When lunar age goes up: Chinese New Year 2024–2030
Everyone's lunar age goes up by one on Chinese New Year's Day, whatever their birthday. In 2027 that is Saturday, February 6. See Chinese New Year 2027.
| Chinese year | Chinese New Year | Year | Leap month |
|---|---|---|---|
| 2024 | Sat, Feb 10, 2024 | Wood Dragon 甲辰 | — |
| 2025 | Wed, Jan 29, 2025 | Wood Snake 乙巳 | Leap 6th month |
| 2026 | Tue, Feb 17, 2026 | Fire Horse 丙午 | — |
| 2027 | Sat, Feb 6, 2027 | Fire Goat 丁未 | — |
| 2028 | Wed, Jan 26, 2028 | Earth Monkey 戊申 | Leap 5th month |
| 2029 | Tue, Feb 13, 2029 | Earth Rooster 己酉 | — |
| 2030 | Sun, Feb 3, 2030 | Metal Dog 庚戌 | — |
Lunar age, Western age and Korean age
- Western (international) age starts at 0 and adds a year on each birthday.
- Chinese lunar age (虚岁) starts at 1 and adds a year at each Chinese New Year. It is traditional; official documents in China use Western age.
- Korean age also starts at 1, but adds a year for everyone on January 1. Since June 28, 2023, South Korea has used international age for most legal and administrative purposes.
Korean age and Chinese lunar age usually agree, but around the turn of the year they can differ by one: Korean age goes up on January 1, and Chinese lunar age at Chinese New Year.
Questions
How do I find out my lunar age?
Take the current Chinese year, subtract the Chinese year you were born in, and add 1. Chinese years start at Chinese New Year, so if you were born in January or February before that year's New Year, your Chinese birth year is the previous one. The calculator above does this for any date.
How can I calculate my lunar age for 2026?
From Chinese New Year 2026 (February 17, 2026) to the day before Chinese New Year 2027 (February 5, 2027), lunar age is 2026 minus your Chinese birth year plus 1. Someone born on March 10, 1990 is 37 in that period, and 38 from February 6, 2027.
Does lunar age change on my birthday?
No. Lunar age goes up for everyone at Chinese New Year, whatever their birthday. Your Western age is the one that changes on your birthday.
How do I calculate the mother's lunar age at conception?
Use the same rule on the conception date: the Chinese year of conception minus the Chinese year of the mother's birth, plus 1. It is her age when the baby was conceived, not at the birth. If you only know the due date, conception was about 266 days (38 weeks) before it.
How do I find the lunar month of conception?
Convert the conception date to the Chinese calendar; the month number is the one the gender chart uses. If it falls in a leap month, most people use the month with the same number. The second tool above gives both values and the dates the month runs from and to.
Is lunar age the same as Korean age?
Not quite. Both count 1 at birth, but Korean age goes up for everyone on January 1, while Chinese lunar age goes up at Chinese New Year. Since June 28, 2023, South Korea has used international age for most legal and administrative purposes.
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