Synastry Chart Calculator
Overlay two birth charts to discover the planetary connections, compatibility scores, and cosmic chemistry between you and your partner.
What Is a Synastry Chart?
Synastry is the astrological study of relationships by comparing two birth charts. When you overlay one chart on another, the angles (aspects) between the planets reveal the dynamics of the relationship, including areas of harmony, tension, attraction, and growth.
Professional astrologers consider synastry one of the most reliable tools for understanding relationship compatibility. Key aspects to look for include Sun-Moon connections (emotional compatibility), Venus-Mars aspects (physical attraction), and Mercury-Mercury aspects (communication flow).
Key Aspects in Synastry
Conjunction (0 degrees)
Intense blending of energies. Powerful but can be overwhelming.
Trine (120 degrees)
Natural harmony and ease. The most supportive aspect.
Sextile (60 degrees)
Friendly cooperation. Requires effort but flows well.
Square (90 degrees)
Tension and growth catalyst. Challenging but creates sparks.
Opposition (180 degrees)
Magnetic attraction through differences. Push-pull dynamic. Complementary.
Frequently Asked Questions
Is synastry the same as composite charts?
No. Synastry overlays two individual charts to see how the people interact. A composite chart mathematically creates a single chart representing the relationship itself as a third entity.
Can synastry predict if a relationship will work?
Synastry reveals the energetic dynamics between two people, but it cannot predict outcomes. Even challenging aspects can be navigated with awareness and communication. The most important factor is always the individuals themselves.
What's the most important synastry aspect?
Most astrologers consider Sun-Moon aspects the most important for long-term compatibility, as they represent the core identity meeting the emotional needs. Venus-Mars aspects are most significant for physical attraction.
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