Chinese Zodiac Calculator

The Chinese Zodiac Calculator tells you everything about your birth year’s position in the traditional lunisolar cycle — from the famous 12-animal sign all the way to the exact sexagenary pillar (a specific combination within the 60-year grand cycle), your Five-Element nature, Yin or Yang polarity, compatibility pairings, lucky numbers and colours, and the next year your sign recurs. Every calculation happens locally in your browser: no data is transmitted, no account is required, and the results appear instantly.

How the Chinese Zodiac works

The Chinese Zodiac (生肖, Shengxiao) is part of a much larger lunisolar timekeeping system called the sexagenary cycle (干支, Ganzhi). It has two interlocking components:

Twelve Earthly Branches (地支, Dizhi) — the familiar animal year cycle: Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Goat, Monkey, Rooster, Dog, Pig. Each animal governs one year; the cycle repeats every 12 years.

Ten Heavenly Stems (天干, Tiangan) — five elements (Wood, Fire, Earth, Metal, Water), each appearing in a Yang form and then a Yin form, cycling every 10 years.

Because 12 and 10 share a lowest common multiple of 60, the two cycles align only once in every 60 years, producing 60 unique year-names. Your birth year’s pillar — written in romanised form as, say, Jiǎ-Zǐ (the Wood Rat, first pillar) — encodes your animal, element and polarity in one compact label.

The critical New Year boundary

The most common error in Chinese zodiac calculations is assuming the zodiac year begins on 1 January. It does not. The Chinese New Year (Spring Festival) is a lunisolar date that falls between 21 January and 20 February each Gregorian year. Anyone born before that date in a given year belongs to the previous animal year.

This calculator uses an exact lookup table of Chinese New Year dates from 1900 to 2040. For dates outside that range it falls back to a fixed 4 February boundary and flags the result as approximate.

Formula in plain numbers

Given a birth date, the zodiac year Z is determined as:

• If birth date is before that year’s Chinese New Year: Z = Gregorian year - 1
• Otherwise: Z = Gregorian year

Then:

• Animal index = (Z - 4) mod 12 (year 4 CE was a Rat year)
• Stem index = (Z - 4) mod 10
• Element = ELEMENTS[floor(stem / 2)] where ELEMENTS = [Wood, Fire, Earth, Metal, Water]
• Polarity = Yang if stem mod 2 = 0, Yin otherwise

Worked example

Birthday: 15 February 1990

Chinese New Year 1990 fell on 27 January. February 15 is after 27 January, so the zodiac year is 1990.

• Animal index: (1990 - 4) mod 12 = 1986 mod 12 = 6 → index 6 = Horse
• Stem index: (1990 - 4) mod 10 = 1986 mod 10 = 6 → element index floor(6/2) = 3 = Metal; polarity 6 mod 2 = 0 = Yang
• Result: Yang Metal Horse (Gēng-Wǔ)
• Compatibility group: Tiger, Dog
• Lucky numbers: 2, 3, 7
• Lucky colours: Yellow, Green

Birthday: 20 January 1990

January 20 is before the 27 January 1990 New Year, so the zodiac year is 1989.

• Animal index: (1989 - 4) mod 12 = 1985 mod 12 = 5 → Snake
• Stem index: (1989 - 4) mod 10 = 5 → element floor(5/2) = 2 = Earth; polarity 5 mod 2 = 1 = Yin
• Result: Yin Earth Snake (Jǐ-Sì)

The 20-day gap produces a completely different sign — which is exactly why the New Year boundary matters.