Free synastry calculator
Drop in both birth charts and ERA maps the exact contacts between you, where you spark, where you grate, and what the pairing is actually built for.
Sample result
Inner wheel: Person A. Outer wheel: Person B. Lines mark the aspects between them.
Key contacts
Affinity overview
His Venus sits right on her Mars, so the pull is immediate and physical. But the Mars square Saturn means desire keeps running into a wall of caution, the heat is real, but so is the friction over pace and commitment.
This is a pairing that runs hot fast and then has to earn the slow part. Worth it if both of you respect the brake.
A synastry chart overlays one person's planets onto another's and measures the angles between them. Those angles, the aspects, are the real mechanics of how two people affect each other, far past what sun signs alone can tell you.
It is the difference between asking whether your signs are compatible and asking what actually happens when your Moon meets their Mars. ERA reads the second question, because that is where a relationship is decided.
The inner ring holds Person A's planets, the outer ring holds Person B's. Each line drawn across the center is an aspect, a precise angular contact between one person's planet and the other's.
Solid lines tend to ease and flow; tense lines mark the work. A strong pairing usually has both, the flow gives it warmth, the tension gives it something to grow on. ERA tells you which is which and what to do with it.
The pairing at a glance
Other free calculators
Go deeper
No card. Both charts read in minutes.
Start free
Free to start. No credit card. Web and Android.