Synastry in Astrology: How Birth Chart Comparison Works
Updated May 17, 2026 · Astrologist.com Editorial
Synastry is where it all comes together.
Two charts. One interaction.
What synastry is
It compares two birth charts.
Not just signs.
Everything.
This is where most people recognize themselves. It shows up in how you connect with others, how relationships flow, and why some bonds feel stronger than others.
What it looks at
Things like:
- planet connections
- aspects between charts
- house overlays
This shows how people affect each other.
Why it matters
This is the real compatibility layer.
Not simplified.
Actual interaction.
How it works
One chart interacts with the other.
Planet to planet.
That creates aspects:
But this alone doesn't explain the full pattern -- how it plays out depends on the rest of your chart.
Summary
Synastry shows how two people interact in reality. It goes beyond simple matching into actual dynamics. This is just the surface. The real pattern shows up when this interacts with the rest of your chart.