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What is synastry?

Relationship astrology that goes deeper than star signs

The short version

Synastry is the astrology of relationships. Instead of asking whether two star signs get on, it lays one person's chart over another's and looks at where their planets land in your houses, and where yours land in theirs. It works for partners, but also for friends, family, exes and colleagues.

Why star sign compatibility isn't enough

Most compatibility articles only compare two Sun signs, which is one planet out of ten for each of you. Two Scorpios can have very different relationships, because the rest of their charts are different. Synastry uses the whole chart, so it can explain why you click with one Scorpio and clash with another.

Their planets in your houses

Each of your houses covers an area of life. When someone's planet falls in one of them, that part of them shows up in that area of your life. Their Venus in your 7th house, Bonds, often feels like natural partnership. Their Mars in your 5th, Desire, tends to bring chemistry and play. Their Saturn in your 4th, Roots, can feel steadying, or a bit like being parented.

It works both ways

Your planets also land in their houses, and the two directions can feel quite different. You might bring warmth into their home life while they bring drive into your work. Reading both sides gives a fairer picture than reading only one.

See every placement, house by house →

The planets that matter most

For romance, astrologers look first at Venus (what you love), Mars (what you desire) and the Moon (what you need). For friendship and family, the Sun, Moon and Mercury often say more. The slow outer planets show up as background themes rather than day-to-day feelings.

What it can't tell you

Synastry describes the style of a relationship: where it feels easy, where it rubs and what you bring out in each other. It can't tell you whether a relationship will work. That comes down to how two people actually treat each other.

How to see yours

You need both people's birth date, time and place, because houses depend on the birth time. In the Houses app, add someone to Orbit and it places their planets in your houses and yours in theirs, worded for the kind of relationship you have.