Synastry Charts Explained: Check Compatibility

• Synastry overlays two birth charts to reveal attraction, harmony, tension, and growth potential in any relationship.
• Venus-Mars contacts indicate physical chemistry; Moon contacts indicate emotional safety and long-term satisfaction.
• Saturn aspects are essential for lasting relationships — they create commitment and staying power.
• Difficult aspects do not doom a relationship. They highlight areas that require conscious effort and often drive the deepest growth.
• Synastry shows dynamics, not destiny — how you navigate the patterns matters more than the patterns themselves.

for reflection & self-knowledge — not prescription.

Venus-Mars contacts do not guarantee emotional compatibility, but they explain why certain people feel magnetically drawn to each other.

Moon Compatibility

What it indicates: Emotional security, domestic harmony, nurturing patterns.

Moon contacts in synastry reveal how emotionally safe you feel with someone. They are often more important for long-term relationship satisfaction than Venus-Mars aspects.

• Moon-Moon conjunction or trine: You instinctively understand each other's emotional needs
• Moon-Venus: Warmth, affection, and genuine enjoyment of each other's company
• Moon-Jupiter: Emotional generosity, mutual encouragement, feeling emotionally expansive together
• Moon-Saturn: Emotional responsibility and commitment, but can feel restrictive if one person becomes the emotional authority

Saturn Aspects (Long-term Stability)

What they indicate: Commitment, durability, responsibility — but also potential restriction.

Saturn in synastry gets a bad reputation, but it is one of the most important indicators for whether a relationship lasts. Saturn contacts create a sense of obligation and mutual investment that keeps people together through difficulty.

• Saturn-Sun: One person helps structure and ground the other's identity; can become controlling
• Saturn-Moon: Emotional commitment but possible emotional restriction; the Saturn person may feel responsible for the Moon person's feelings
• Saturn-Venus: Serious love, long-term commitment; can feel like love requires work

Relationships with no Saturn contacts often lack staying power. Relationships with only Saturn contacts can feel heavy. The ideal is Saturn contacts alongside Venus-Mars chemistry and Moon compatibility. For a deeper understanding of how these planetary aspects work, see our aspects guide.

Red Flags in Synastry

No single aspect is a dealbreaker, but these patterns warrant awareness:

• Pluto conjunct or square personal planets: Intense, potentially obsessive or controlling dynamics. Transformative but can become destructive without self-awareness.
• Mars square Mars: Frequent conflict over different action styles. Both people want to be in charge.
• Saturn square Moon: Emotional coldness or criticism where nurturing is needed. One person may feel emotionally dismissed.
• Neptune square Venus: Idealization, deception, or confusion about the true nature of the relationship. Things may not be as they appear.
• No personal planet contacts: Lack of meaningful interaction between inner planets can indicate polite indifference rather than a compelling relationship.

Remember: difficult aspects do not doom a relationship. They highlight areas that require conscious effort. Many of the most growth-oriented, long-lasting relationships have prominent squares and oppositions.

How to Read Your Own Synastry

To analyze synastry between you and another person:

1. Generate both natal charts using accurate birth data
2. Identify aspects between Person A's planets and Person B's planets (the key ones: Sun, Moon, Venus, Mars, Saturn contacts)
3. Note the quality of each aspect (conjunction, trine, square, etc.)
4. Look at the overall pattern — is the chart dominated by harmonious aspects, challenging ones, or a mix?

The interpretation is where it gets nuanced. A Venus-Mars square combined with a Moon-Moon trine tells a different story than a Venus-Mars trine with a Moon-Saturn square.

Understanding each person's Big Three is an essential starting point — the interplay between your Sun, Moon, and Rising signs often reveals the initial dynamic. For a deeper context, consider how planetary transits are currently affecting each person's chart, as transits can activate or soften synastry dynamics.

How to Get a Free Synastry Reading

If you want to explore compatibility with a partner, friend, or colleague, Natal AI's chatbot can analyze synastry between two charts. Enter both birth dates and ask specific questions about how your charts interact.

For a foundation in reading your own chart first, start with our birth chart reading guide or learn about your Sun, Moon, and Rising signs. To understand the houses that each person's planets activate, check our houses guide.