Astrology Compatibility Calculator
Enter two birth dates and see how the two charts actually get along: the pulls, the friction and where each of you leans on the other. Free, with a written summary in about a minute.
What you get
- 1Both charts, overlaid. Every planet in one chart set against every planet in the other, in the tropical and true sidereal zodiacs.
- 2Four scores, not one number. Attraction, emotional rhythm, communication and long-term fit are scored separately, because couples rarely match evenly on all four.
- 3A written summary. The strongest connections and the clearest friction points, in plain language, before you decide whether to read further.
Why two full charts beat two sun signs
Sun-sign compatibility compares one placement out of more than twenty. Two people with "incompatible" sun signs can have Moons that understand each other instantly and a Venus–Mars contact that explains the whole attraction. A compatibility calculator that reads the full chart sees those.
The technical name for this comparison is synastry. You do not need to know the word to use the calculator; the result explains each connection as it comes up.
Want the full method, aspect by aspect? Read the synastry guide
Common questions
What does an astrology compatibility calculator actually do?
It overlays two birth charts and measures the angles between every planet in one chart and every planet in the other. Close angles show where the two people pull together or rub against each other. This calculator does that in two zodiac systems and scores four separate dimensions.
Is it accurate if I only know our sun signs?
Sun signs are one placement each. The calculator needs both birth dates and, ideally, birth times and places, because the Moon, Venus, Mars and the rising sign carry most of what people experience as chemistry or friction.
What if one of us does not know their birth time?
You can still run it. Tick "unknown birth time" for that person: planets are placed for noon, so the rising sign and houses are left out and Moon contacts are marked as approximate.
Is this compatibility calculator free?
Yes. The overlay, the four scores and the written summary are free. A longer written reading of the relationship is a separate paid option shown on the result page.
Compatibility summaries are generated by artificial intelligence for entertainment and self-reflection only. They are not a substitute for professional relationship counseling.