Harmony
Trines and sextiles often describe energy that flows with less effort between two people.
Two charts in conversation
Synastry Compatibility Calculator
Synastry compares the real angles between two birth charts. It can show ease, attraction, friction, and themes that repeat between you—without pretending a relationship can be reduced to one percentage score.
- Real ephemeris
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Compare two birth charts
Enter both sets of birth details. Exact times improve rising signs and angles; the planetary cross-aspects remain useful without them.
Calculation accuracy
Compatibility is a pattern, not a verdict
This calculator measures major aspects between the ten core planets in both charts and ranks the tightest contacts first. Smaller orbs describe more exact geometry.
Harmony does not guarantee a lasting relationship, and tension does not make one doomed. Synastry describes interaction patterns; choices, circumstances, communication, and consent remain more important than any chart.
See our calculation methodology →Read the result
How to read your comparison
Tension
Squares and oppositions can create friction, polarity, motivation, and growth—not automatic failure.
Fusion
Conjunctions combine two planetary functions strongly; the planets involved determine the tone.
Orb
The closer an aspect is to exact, the more clearly that cross-chart contact tends to register.
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Clear answers
Synastry Compatibility Calculator FAQ
What is synastry?
Synastry is the comparison of two natal charts, especially the geometric aspects made from one person's planets to the other person's planets.
Is there a reliable astrology compatibility score?
No single score can responsibly summarize two charts. A relationship can contain supportive and difficult patterns at the same time, so this tool shows the evidence instead.
Can I compare charts without both birth times?
Yes for planetary aspects. Unknown times make the Moon less certain on sign-change days and prevent reliable use of rising signs, houses, and angles.
Which synastry aspects matter most?
Tight contacts involving the Sun, Moon, Venus, Mars, and Saturn are commonly felt, but repeated body pairs and the full pattern matter more than one isolated aspect.
Does a difficult aspect mean we should separate?
No. Astrology is not a substitute for your lived experience or safety. Difficult aspects describe possible friction, not a command or fixed outcome.
See your real pattern first