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Synastry Compatibility Calculator

Compare two birth charts for relationship insights

Explore the astrological chemistry between any two people with our professional synastry calculator. By overlaying two natal charts, synastry reveals the inter-aspects that create attraction, harmony, tension, and growth in relationships — whether romantic, platonic, or professional.

What Synastry Reveals

  • ✓Inter-aspects between both charts (how your planets interact with theirs)
  • ✓Composite chart — the midpoint chart representing your relationship as its own entity
  • ✓Venus-Mars connections revealing romantic and sexual chemistry
  • ✓Moon compatibility showing emotional understanding and nurturing styles
  • ✓Saturn aspects indicating long-term commitment potential and challenges
  • ✓Nodal connections highlighting karmic ties and soul-level purpose together
  • ✓House overlays showing which life areas your partner activates in you
  • ✓Overall compatibility score based on harmonious vs. challenging aspects

How It Works

1

Enter Both Birth Details

Provide the date, time, and place of birth for both individuals. Accurate birth times help calculate house overlays and ascendant connections.

2

Charts Are Compared

Our engine calculates both natal charts independently, then overlays them to find every inter-aspect, house overlay, and composite midpoint between the two charts.

3

Explore Your Connection

Receive a comprehensive analysis covering romantic chemistry, emotional compatibility, communication style, shared challenges, and long-term potential.

Calculator Features

💕

Complete Inter-Aspect Grid

Visual grid showing every aspect between both charts — from major conjunctions to subtle sextiles — with orbs and strength ratings.

🔮

Composite Chart Generation

Automatically generates the composite midpoint chart, revealing the unique energy and purpose of the relationship itself.

📈

Compatibility Scores

Detailed scoring across multiple dimensions: romance, emotional connection, communication, growth potential, and long-term stability.

🌙

Emotional Compatibility

Deep analysis of Moon signs, Moon aspects, and Venus placements to understand emotional needs and love languages.

⚡

Chemistry Indicators

Identifies Venus-Mars connections, Pluto aspects, and 5th/8th house overlays that create magnetic attraction.

🔗

Karmic Connections

North Node, South Node, and Saturn aspects that reveal past-life ties and the deeper purpose of your connection.

Frequently Asked Questions

What is a synastry chart?▾
A synastry chart is created by overlaying two natal birth charts to analyze how the planets of one person interact with the planets of another. These inter-aspects reveal the dynamics of attraction, compatibility, conflict, and growth in any relationship. It is the primary astrological tool for relationship analysis.
Do I need both people's birth times?▾
Ideally, yes. Having accurate birth times allows us to calculate house overlays and Ascendant connections, which add significant depth to the analysis. Without birth times, we can still analyze planet-to-planet aspects and sign compatibility, but the house-level insights will be unavailable.
What's the difference between synastry and a composite chart?▾
Synastry looks at how two individual charts interact — Person A's planets aspecting Person B's planets. A composite chart creates a single new chart using the midpoints of both people's planets, representing the relationship as its own entity with its own personality, purpose, and challenges.
Can synastry predict if a relationship will work?▾
Synastry reveals the natural dynamics, strengths, and challenges in a relationship, but it cannot predict outcomes. Even challenging aspects can lead to profound growth if both people are committed. The chart shows potential and tendencies, not fate. Free will always plays a role in how a relationship unfolds.
Can I use synastry for non-romantic relationships?▾
Absolutely! Synastry works for any type of relationship — friendships, parent-child bonds, business partnerships, mentor-student dynamics, and more. The aspects between charts reveal dynamics that are relevant regardless of the nature of the relationship.

Compare Your Charts Now

Enter birth details for both people and discover the astrological dynamics of your connection. Free and instant results.

Create Synastry Chart