What Synastry Actually Measures (and What It Doesn't)
Relationship astrology compares two charts to map where you flow and where you spark. Here's what a synastry reading can show — and why no single aspect makes or breaks a bond.
Synastry is the astrology of relationship: it lays two natal charts over each other to see how one person’s planets touch the other’s. It’s one of the most popular things people do with astrology, and also one of the most misunderstood.
What it shows
When two charts meet, their planets form aspects to each other — the same angles you’d read within a single chart, now running between two people:
- Harmonious aspects (trines and sextiles) tend to feel easy and supportive — the places where you just get each other.
- Conjunctions fuse two energies, intensifying whatever they touch.
- Squares and oppositions create friction and magnetism — the charge that keeps a connection alive, and the edges you have to work with.
The most telling connections are usually between the personal planets: Sun, Moon, Venus and Mars. A Moon touching a partner’s Venus, for instance, often shows up as a deep, instinctive warmth.
What it doesn’t show
Here’s the part the dramatic apps leave out: no single aspect makes or breaks a relationship. A chart full of trines can coast into complacency; a chart full of squares can build something durable precisely because the friction demands attention.
A synastry score — including our own resonance number — is best read as a playful summary, not a verdict. Real relationships are built, not predicted. The chart only shows the raw material; what you make of it is up to the two of you.
Try it yourself
Pull up two charts and see the aspects between them with our compatibility reading. Then read how aspects work to understand what each connection is actually saying.
Reading about charts is one thing — seeing your own is another. It takes about thirty seconds.