Instantly calculate the core elemental compatibility of two natal charts to understand the natural flow and friction points in your relationship.
Synastry Chart Compatibility Calculator
Synastry Chart Calculation Formula
Compatibility Score $\propto \sum_{i} (W_i \times A_{i,j})$
Where $W_i$ is the weight of Planet $i$ (e.g., Moon/Venus high weight, Mars/Pluto medium), and $A_{i,j}$ is the elemental harmony value between P1’s Planet $i$ and P2’s Planet $j$. This calculator uses a simplified Elemental Comparison:
Formula Source: Astro.com – Synastry | Cafe Astrology – Relationship Analysis
Variables
- Person 1 Name/P2 Name: Identifiers for the two individuals.
- P1 Birth Date/P2 Birth Date: The date of birth for each person. This input is crucial for determining the Sun Sign and its associated Element (Fire, Earth, Air, Water), which forms the basis for the compatibility score.
- Birth Time/Location (Not Used in Simplified Model): In full synastry, these are required to determine Ascendant, Midheaven, and precise house placements, offering deeper context.
Related Calculators
- Natal Chart Finder (Low Competition Keyword)
- Planetary Retrograde Schedule (Low Competition Keyword)
- Composite Chart Analysis (Low Competition Keyword)
- Midpoint Interpretation Tool (Low Competition Keyword)
What is a Synastry Chart Calculator?
A Synastry Chart Calculator is a fundamental tool in relationship astrology. “Synastry” literally means “stars together,” and the chart is generated by superimposing one person’s natal (birth) chart onto another’s. This comparison reveals how the planets, signs, and houses in one chart interact with the other, highlighting areas of harmony, attraction, and potential friction.
The resulting analysis goes far beyond simple sun sign compatibility. It provides insights into emotional connection (Moon aspects), communication styles (Mercury aspects), physical attraction (Mars aspects), values (Venus aspects), and long-term commitment (Saturn aspects). It is used to understand romantic partnerships, family dynamics, business relationships, and friendships.
How to Calculate Synastry Chart Compatibility (Example)
- Input Data: Enter Person A’s birth date (e.g., 1990-04-10) and Person B’s birth date (e.g., 1988-11-05).
- Determine Sun Signs: Person A (April 10) is an Aries. Person B (November 5) is a Scorpio.
- Identify Elements: Aries is a Fire sign. Scorpio is a Water sign.
- Apply Compatibility Rule: Fire and Water are considered a challenging combination, as Fire (action, spirit) conflicts with Water (emotion, depth).
- Generate Score and Interpretation: The calculator assigns a numerical score (e.g., 55%) and provides an interpretation reflecting the dynamic tension between these elements.
Frequently Asked Questions (FAQ)
- What is the difference between Synastry and Composite charts? A Synastry chart overlays two individual charts to show their interaction; a Composite chart is a single, unified chart representing the relationship itself, calculated from the midpoint of all corresponding planets.
- Does the Synastry Calculator predict the future? No, astrology does not predict the future. It highlights inherent energies and tendencies within a relationship, offering self-awareness tools to navigate potential challenges and maximize positive interactions.
- Are the results guaranteed to be accurate? The compatibility score provides a starting point based on core astrological factors. A full, professional synastry reading includes many more variables (houses, specific aspects, and midpoints) for complete accuracy.
- Why do I need the birth time and location? Birth time and location are required to determine the Ascendant (Rising Sign) and the House placements of the planets. These details are vital for understanding how the relationship plays out in the practical, daily life areas (work, home, finance).