Western Astrology
Synastry Beta
How two charts meet — the inter-aspects between your planets, where each person falls in the other's houses, the composite midpoint chart, and a compatibility score.
Choose two people to compare
Synastry compares two charts — you'll need at least two saved profiles, each with a birth place.
Date
Birth date for both people
Time
Birth time for houses and angles
Place
Birth place with timezone
What is synastry?
Synastry compares two birth charts to read a relationship — how one person's planets touch the other's, where there's chemistry, and where there's friction.
It doesn't reduce a couple to a single number. It maps the specific contacts: your Venus to their Mars, your Moon to their Saturn, and what each tends to feel like.
How to read it
Inter-aspects are the heart of it — aspects between one chart's planets and the other's. Sun–Moon and Venus–Mars contacts build attraction; Saturn contacts bring weight, commitment, or restriction.
House overlays show where one person's planets land in the other's houses — the life areas they light up for each other. The composite chart treats the relationship itself as a third entity.
Key ideas
Angles between the two charts' planets — the direct chemistry and friction between you.
Where your planets fall in their houses, and theirs in yours — the areas you activate for each other.
A single midpoint chart for the relationship as its own being, apart from either person.
A relationship chart cast for the midpoint in time and space between two births — a real chart, not a construct.
Common questions
Where it comes from
Comparing charts for relationships is old, but detailed synastry — and the composite and Davison methods — took their modern form in the 20th century, alongside psychological astrology.