Synastry Calculator
Compare two birth charts side by side. See where you click, where you clash, and what makes your connection unique.
What is synastry?
Synastry overlays two birth charts to map the dynamics between two people. Each person's planets form aspects — conjunctions, squares, trines — with the other's, creating a picture of how the relationship actually works.
Synthesis runs synastry in both Tropical and True Sidereal systems. Two lenses on the same connection — personality-level patterns and deeper structural dynamics.
Synastry readings are generated by artificial intelligence for entertainment and self-reflection purposes only. They are not a substitute for professional relationship counseling.
Questions
What is a synastry chart?
A synastry chart overlays two birth charts to analyze relationship dynamics. It shows how one person's planets aspect another's, revealing areas of harmony, tension, and growth between two people.
How is synastry different from a composite chart?
Synastry compares two separate charts side by side, showing how each person affects the other. A composite chart merges both charts into one, representing the relationship itself as its own entity.
Do I need an exact birth time for synastry?
Birth time improves accuracy — especially for Rising sign and house placements. Without it, the core planet-to-planet aspects (Sun, Moon, Venus, Mars) are still meaningful.
What systems does Synthesis use for synastry?
Synthesis calculates synastry in both Tropical and True Sidereal systems, giving you two perspectives on the same relationship. Each system highlights different dynamics.