Composite Charts: The Relationship's Own Chart
Synastry compares two people. A composite chart does something different: it combines two birth charts into one, and the result is read as the chart of the relationship itself.
How a composite chart is built
Each point in a composite chart is the midpoint between the same point in the two birth charts. The composite Sun sits halfway between your Sun and theirs, the composite Moon halfway between your Moons, and so on for every planet and point. The result belongs to neither person, because no one was born at that moment. It describes what the two of you form together.
There are other ways to make a relationship chart. The Davison chart, for example, uses the midpoint of the two birth dates, times and places. The composite chart, built from planetary midpoints, is one of the best known, and it's the one we draw.
How to read it
Read it as you would a birth chart, but ask the questions of the relationship rather than of a person.
- The Sun: the purpose and identity of the relationship, what it is about.
- The Moon: its emotional life, and what makes it feel safe.
- The Ascendant: how the relationship appears to other people.
- Venus: how affection is shown and what the two of you value.
- Mars: drive and desire, and how disagreements play out.
- Mercury: how you communicate.
- Saturn: commitment, structure and responsibility.
The signs describe the style of each, the houses show which areas of shared life the themes play out in, and the aspects show how the different parts work together.
Composite or synastry?
They answer different questions. Synastry asks how two people affect each other. The composite chart asks what the relationship is like as a whole. Astrologers often use both: synastry for the interplay, the composite for the character of the union. Neither is a score.
Where to begin
Start with the composite Sun, Moon and Ascendant, then the tightest aspects. Our free composite calculator draws the chart from two sets of birth details, and our guide to synastry covers the other side of the picture.