Understanding Synastry: How GemZen Calculates Relationship Compatibility

Beyond Sun Sign Compatibility

If you've ever read that "Aries and Leo are compatible" or "Virgo and Pisces are opposites," you've encountered Sun sign compatibility — the most simplified form of relationship astrology. Real synastry is far more nuanced and revealing.

GemZen's synastry engine compares the complete birth charts of two people, calculating every aspect between Person A's planets and Person B's planets. The result isn't a single number but a multidimensional picture of how two people interact.

Four Dimensions of Compatibility

Harmony — How naturally your energies flow together. High harmony means ease, understanding, and comfort. Measured through trines and sextiles between personal planets.

Passion — The magnetic pull and intensity between you. Venus-Mars contacts, Pluto aspects, and 5th/8th house overlays drive this score.

Challenge — Areas of friction and growth. Squares and oppositions create tension that can either strengthen or stress a relationship.

Growth — How much you help each other evolve. North Node contacts, Jupiter aspects, and Saturn connections indicate soul-level development.

Relationship Themes

Beyond scores, our engine automatically detects relationship themes: emotional bonds (Sun-Moon contacts), physical attraction (Venus-Mars), karmic lessons (Saturn contacts), destined connections (Node contacts), and transformative intensity (Pluto contacts).

Try synastry at /astrology/synastry" style="color:#d4a574;text-decoration:underline">astrology/synastry — enter two birth dates and see what your charts reveal.