Free Synastry Chart Calculator
Synastry compares two natal charts to show where one person activates the other. Regu keeps the comparison structured with inter-chart aspects, house overlays, and related two-chart tools.
What the synastry calculator shows
- Inter-chart aspects between two people
- House overlays that show where each chart lands in the other chart
- Orb-based technical context for the strongest contacts
- A starting point for composite and relationship pattern summaries
Best reading flow
- Enter both people with the most accurate birth time and place available.
- Review the strongest inter-chart aspects before focusing on one placement.
- Use composite or aspect matrix tools when you want a more technical second pass.
Why this page exists
Relationship calculators can flatten a bond into a score. Regu is built around the pattern: aspects, house overlays, repetition, and structure stay visible so the reading remains grounded.
Continue the relationship reading
Common questions
What is synastry?
Synastry compares two birth charts. It looks at how one person’s planets aspect the other person’s planets and where each chart falls into the other chart’s houses.
Is synastry the same as a compatibility score?
No. Synastry is more useful as a pattern map than a yes-or-no score. It can show attraction, tension, repetition, and areas of focus between two charts.
Do both people need exact birth times?
Exact birth times are best because houses and angles depend on time. If one time is unknown, planet-to-planet aspects can still be useful, but house overlays are less precise.