Free tool
Compare two birth charts
Enter both birth details and see every aspect between the two charts, grouped into harmony, intensity and friction — each score built from the named aspects behind it, not handed to you as a verdict.
Synastry questions
- What is synastry?
- Overlaying two birth charts and reading the aspects between them — where one person's Venus falls against the other's Mars, for instance. It describes dynamics between two people, not a compatibility percentage.
- Why three categories instead of one score?
- A single number hides the mechanism. Harmony, intensity and friction are each a transparent sum of the actual aspects contributing to it, listed underneath — so you can see exactly what the score is built from and weigh it yourself.
- Is a high friction score bad?
- Not inherently. Square and opposition aspects create tension, and tension is often what makes a relationship feel alive rather than what breaks it. Read friction alongside harmony, not instead of it.
- Do I need to know both birth times?
- For the Sun, Moon and planet-to-planet aspects, no — those barely move across a day. For house overlays and the Ascendant/Midheaven, yes, and an unknown time is marked rather than guessed at.
Positions are computed with the Swiss Ephemeris. Astrology is not a science, and nothing here is medical, legal or financial advice.