Western Astrology · Sun-Sign Synastry
Zodiac Compatibility Calculator
Pick any two star signs for an instant 0–100 match score and a full reading across love, friendship and communication — grounded in classical synastry, not guesswork.
Explore each sign's compatibility
How zodiac compatibility works
Every sun sign carries an element (fire, earth, air or water) and a modality(cardinal, fixed or mutable). The relationship between two signs is read from the angle between them on the zodiac wheel — astrologers call this the aspect. Trines (signs four apart, always the same element) flow effortlessly; squares (three apart) create the friction that fuels growth; oppositions (six apart) are the classic “opposites attract.”
Our calculator turns that classical logic into a single, repeatable 0–100 score, then breaks the match down into the parts that actually matter day to day: romance, friendship, communication, where the friction shows up, and what to do about it. Choose your two signs above, or open any sign below to see how it pairs with all twelve.
Go beyond your sun sign
Compatibility is the sun-sign layer. Map the rest of your chart with a free reading.
Frequently asked questions
How is zodiac compatibility calculated?▾
We use classical Western-astrology synastry: the angular relationship between your two sun signs on the 12-sign wheel (trine, sextile, square, opposition and so on), combined with how your elements (fire, earth, air, water) and modalities (cardinal, fixed, mutable) interact. The same pair always returns the same score.
Which zodiac signs are the most compatible?▾
Signs of the same element (two fire, two earth, two air or two water signs) sit a trine apart and tend to flow together most easily. Complementary elements — fire with air, earth with water — also pair beautifully. The calculator scores every one of the 144 possible matches so you can compare.
Do opposite signs attract?▾
Often, yes. Opposite signs sit across the wheel from each other and each owns exactly what the other lacks, which is magnetic. They score well but need conscious balancing — the attraction is real, and so is the work.
Is sun-sign compatibility the whole picture?▾
No. Sun signs are the headline, but a full synastry reading also weighs the Moon, Venus, Mars and the rising sign. This calculator focuses on the sun-sign layer, which is the most influential single factor and the one almost everyone knows.