Lunar Age Calculator
Enter your Gregorian birth date and get your lunar age - the traditional East Asian count where you are 1 at birth and gain a year every Lunar New Year - alongside your international age, your Chinese zodiac animal, and the date you next age up.
In the traditional count a baby born the day before Lunar New Year turns 2 the next morning - age marks the number of calendar years you have touched, not years elapsed.
How lunar (East Asian) age works
In the traditional East Asian count - Chinese xusui, and the closely related traditional Korean and Vietnamese systems - a baby is 1 at birth, and everyone gains a year together at the new year rather than on individual birthdays. In the Chinese system the increment happens at Lunar New Year, which falls between January 21 and February 20 on the Gregorian calendar.
That makes lunar age either one or two years higher than Western age: two if the next Lunar New Year has passed but your Gregorian birthday has not (or you were born in the window before that year's New Year), one otherwise. A baby born in late January can be 2 years old within days.
Where the count still matters
Lunar age is still used informally across China, Vietnam (tuoi mu), and among older generations in Korea for things like zodiac matching, some temple and fortune-telling customs, and stating ages of elders. Official documents in all of these countries use international age. Your zodiac animal follows the lunar year of birth, so a January baby born before Lunar New Year belongs to the previous year's animal - a common surprise.
How it’s calculated
Lunar age = (current lunar year − birth lunar year) + 1, where a date's lunar year equals the Gregorian year if the date falls on or after that year's Lunar New Year, otherwise the year before. Lunar New Year dates for 1940-2030 come from published Gregorian-lunar conversion tables (Hong Kong Observatory); outside that range February 4 is used as an approximation and the result is flagged. Zodiac animal = birth lunar year mapped onto the 12-year cycle (2020 = Rat). Western age is the standard calendar age.
Dates are taken in your device's local calendar; for births on Lunar New Year's Day itself the new lunar year is assumed to have started, though historical usage varies by region.
Lunar New Year dates and zodiac animals
| Year | Lunar New Year | Animal |
|---|---|---|
| 2024 | February 10 | Dragon |
| 2025 | January 29 | Snake |
| 2026 | February 17 | Horse |
| 2027 | February 6 | Goat |
| 2028 | January 26 | Monkey |
Source: Hong Kong Observatory Gregorian-lunar calendar conversion tables.
Common mistakes
- Adding 1 to your Western age and calling it done - lunar age can be 2 higher, depending on where today and your birthday sit relative to Lunar New Year.
- Using January 1 as the age-up date: that is the traditional Korean solar convention, not the Chinese lunar one, and the two can differ by up to 7 weeks.
- Assigning a January or early-February baby the new year's zodiac animal - before Lunar New Year the old animal still applies.
- Confusing lunar age with age on the lunisolar calendar's own months - the count only cares about which lunar year you were born in, not the lunar month or day.
Frequently asked questions
How is lunar age calculated?
Lunar age = current lunar year − birth lunar year + 1. You are 1 at birth and add a year each Lunar New Year, so the count equals the number of lunar calendar years your life has touched.
Why is my lunar age two years higher than my real age?
You start at 1 instead of 0 (one year), and if the Lunar New Year has already passed this year while your Gregorian birthday has not, the counts diverge by a second year. After your birthday the gap drops back to one.
Is lunar age the same as Korean age?
They share the born-at-1 logic, but traditional Korean age adds the year on January 1 of the solar calendar, while Chinese lunar age adds it at Lunar New Year, which falls between January 21 and February 20. For people born between those dates the two systems can disagree.
What determines my Chinese zodiac animal?
The lunar year you were born in, on a 12-year cycle (2020 Rat, 2021 Ox, and so on). If you were born in January or early February before that year's Lunar New Year, your animal is the previous year's.
Do official documents use lunar age?
No. China, Korea, Vietnam, and Japan all use international age for legal and administrative purposes; lunar age survives in social and traditional contexts like zodiac years and honoring elders' milestone birthdays.