What this calculator does
Find your star sign and your Chinese zodiac animal from your birthday. Two different calendars each give you a sign. The Western zodiac splits the year into twelve date ranges, named after star patterns in the sky. So your sun sign (your everyday "star sign") depends only on the month and day you were born.
The Chinese zodiac names whole years after twelve animals and five elements, so it depends on the year. But that year starts on Lunar New Year, not January 1. Lunar New Year moves around, landing between January 21 and February 20.
This calculator looks up both signs for you. It flags a birthday on a cusp, the first or last day of a sign. For the Chinese zodiac, it checks your birthday against that year's Lunar New Year. Those dates come from the Hong Kong Observatory's published calendar tables for 1901 to 2100. So if you were born in January or early February, you correctly get the previous year's animal. It's a calendar lookup only. It makes no claims about personality or fortune.
Where it's used
Why this math matters outside the classroom:
- Remainders in action. Students find the 2026 animal by working out (2026 − 4) ÷ 12 = 168 remainder 6, the Horse, the seventh animal.
- Cultural celebrations. Families planning Lunar New Year gatherings check that the Year of the Horse begins on February 17, 2026.
- Birthday cards. Someone born on February 10, 1991 learns their animal is the 1990 Horse, since Lunar New Year 1991 was February 15.
- Calendar patterns. Classes notice that a Fire Horse year returns every 60 years, so the last one before 2026 was 1966.
How to use it
- Enter a date of birth between January 1, 1901 and December 31, 2100.
- Read your sun sign at the top, with its date range. A note appears if your birthday is on a cusp.
- Below it, read your Chinese zodiac animal, element, and yin or yang. You'll also see the dates of that lunar year.
- Open the working to see the Lunar New Year check. It also shows the short division sums that pick the animal and element.
What the inputs mean
- Date of birth
- Your date of birth. You don't need the time or place of birth for these lookups. The one exception is a cusp birthday, where only the exact moment the Sun changed sign could settle it.
Formula and method
Sun sign = the range containing the birth month and day (Aries Mar 21 – Apr 19, … Pisces Feb 19 – Mar 20) Lunar year = birth year, or birth year − 1 if the birth date is before that year's Lunar New Year Animal = [Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Goat, Monkey, Rooster, Dog, Pig][(lunar year − 4) mod 12] Element = [Wood, Fire, Earth, Metal, Water][floor(((lunar year − 4) mod 10) ÷ 2)] Yang if (lunar year − 4) mod 10 is even, yin if odd
The Western ranges follow the Sun's yearly path through the sky, using the tropical zodiac (the version tied to the seasons). The day the Sun passes from one sign to the next can shift by a day, depending on the year and time zone. So the calculator uses the usual, conventional ranges. Birthdays on the first or last day of a range are marked as cusps.
In the formulas, "mod" means the remainder left after dividing: 22 mod 12 is 10. "Floor" means round down to a whole number. The Chinese animals run in a fixed 12-year order, and the element changes every two years. Together they repeat every 60 years.
Subtracting 4 from the year lines the count up with the start of a cycle. For example, 1984 was a Wood Rat year, the first of the current 60. The year used is the lunar year. It begins on Lunar New Year, the new moon that starts the first month of the Chinese calendar.
Lunar New Year dates come from a table, not a formula. That's because they depend on when the new moon falls in China's time zone. The table holds all 200 dates from 1901 to 2100, as published by the Hong Kong Observatory.
Worked example
Find the zodiac signs for a birth date of January 24, 1990.
- January 24 falls in the range Jan 20 – Feb 18, so the sun sign is Aquarius.
- Lunar New Year in 1990 was on January 27, three days later. So the birth date belongs to the lunar year that began on February 6, 1989.
- Subtract 4 and find the remainder after dividing by 12: (1989 − 4) mod 12 = 5. Counting from Rat at 0, the sixth animal is the Snake.
- Now the remainder after dividing by 10: (1989 − 4) mod 10 = 5. Half of 5, rounded down, is 2, which points to the third element: Earth. The remainder is odd, so it's a yin year.
Result: Sun sign Aquarius; Chinese zodiac Earth Snake (yin), for the lunar year Feb 6, 1989 – Jan 26, 1990.
Understanding the result
If you were born in January or February, check the lunar year dates. Many printed charts list animals by the regular (Gregorian) calendar year alone. That gives the wrong animal to anyone born before that year's Lunar New Year.
A cusp note means your birthday is the first or last day of a sign's usual range. In some years the Sun changes sign on that very day. To settle it, check an astronomical ephemeris (a table of where the Sun was) for your birth year and time.
Assumptions and limitations
- Western signs use the usual tropical (season-based) date ranges.
- Chinese zodiac years begin on Lunar New Year as listed in the Hong Kong Observatory tables. Those tables use the date in China's time zone.
- Dates before 1901 or after 2100 aren't covered by the Lunar New Year table.
- Cusp days can't be settled without your birth time and the exact moment the Sun changed sign that year.
- Some traditions start the zodiac year at Lichun, around February 4, instead of Lunar New Year. This calculator uses Lunar New Year.
Frequently asked questions
Why did I get a different Chinese zodiac animal than my birth year suggests?
It's because the Chinese zodiac year starts on Lunar New Year, not January 1. Someone born on January 24, 1990 arrived before Lunar New Year on January 27, 1990. So their animal is the 1989 Snake, not the 1990 Horse.
What is a cusp?
It's the first or last day of a sign's date range. The Sun moves into the next sign at a set moment, and that moment drifts by up to about a day from year to year. So a cusp birthday can belong to either sign, depending on the year and time you were born.
What do the elements and yin and yang mean here?
They're part of the calendar's naming system. Each of the five elements lasts two years in a row: the first is yang and the second is yin. Combined with the 12 animals, they make a 60-year cycle. For example, 2026 is a Fire Horse year, and a yang year.
When is the next Lunar New Year?
The working shows the Lunar New Year for the year of the date you enter, and the result shows when that lunar year ends. In 2026 it fell on February 17; in 2027 it falls on February 6.
Sources
- Hong Kong Observatory: Gregorian-Lunar Calendar Conversion Table (yearly files, 1901–2100; 2026 shown) (checked 2026-10-19)
How this calculator is checked
Method: Conventional tropical sun-sign date ranges; Chinese zodiac animal and element by the 60-year sexagenary cycle anchored on 1984 (Wood Rat); Lunar New Year dates 1901–2100 from the Hong Kong Observatory Gregorian-Lunar Calendar Conversion Tables. The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-18. Found a problem? Tell us.
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