Composite chart meaning: one chart for two people

A composite chart is a single chart made from two birth charts. For every planet it takes the point halfway between your position and your partner's, the midpoint. Astrologers read the result as a picture of the relationship itself: what the two of you are like together, as distinct from what each of you is like alone. It describes tendencies and gives no verdict.

How a composite chart is calculated

Start with the two Suns. Each stands at a certain degree of the zodiac, the circle of twelve signs with 360 degrees. Find the point halfway between them, going the shorter way around the circle. That point is the composite Sun. Then do the same for the two Moons, the two Venuses, and so on through every planet.

An example. One of you has the Sun at 10° Aries, the other at 10° Leo. The two points are 120 degrees apart, so the midpoint lies 60 degrees from each: at 10° Gemini. Neither of you is a Gemini. The relationship has a Gemini Sun.

Three things follow from this method.

• It is not a sky that ever existed. A birth chart shows a real moment. A composite chart is arithmetic. In a birth chart Venus is never more than about 47 degrees from the Sun. In a composite chart the two can end up far apart, even opposite each other.
• The planets need two dates of birth. The Moon changes signs about every two and a half days, so its midpoint is only exact with both birth times.
• The Rising sign and the houses need both birth times. The Rising sign (also called the Ascendant) is the sign on the eastern horizon at birth, and the houses are the twelve sections of a chart linked to areas of life. Astrologers use more than one method to derive them for a composite.

Some astrologers work with a different technique: a chart for the moment and the place halfway between the two births. That is a separate chart with its own positions. Everything below refers to the midpoint chart.

Composite chart and synastry: the difference

Synastry is the other way to look at two charts: both stay as they are and are compared planet by planet. How synastry aspects are read

The two answer different questions, so one does not replace the other. Astrologers usually read synastry first and the composite second.

Synastry asks what two people do to each other. The composite chart asks what they are together.

What the composite chart is read as

A composite chart is read much like a birth chart, with one change: every statement is about the pair.

The surprising part is that a composite planet often stands in a sign neither of you has. Take a Moon at 15° Scorpio and a Moon at 15° Pisces, two water Moons, both read as feeling deeply. Their midpoint is 15° Capricorn, an earth sign. Astrologers would read this as two sensitive people whose relationship feels safest when it is reliable: plans that hold, promises that are kept.

The angles between composite planets are read as well. Angles of 60 and 120 degrees are read as easy, angles of 90 and 180 degrees as tense, just as in a single chart. With both birth times the houses add where the relationship lives. A composite Sun in the fourth house, the house of home and roots, points to a bond that is mostly lived at home. In the tenth house, the house of career and public role, it points to one that is visible to others or built around shared work. What the twelve houses mean

What a composite chart is not

• Not a verdict. There is no good or bad composite chart. Each one describes a character, with easy sides and demanding ones.
• Not a replacement for two people. Each of you keeps your own chart, your own needs and your own choices. The relationship has a character. It does not have a will of its own.
• Not a forecast. A composite chart does not show how long a relationship lasts or how it ends. It describes how a bond tends to feel, and people decide what they do with that.
• Not only for couples. The same method is used for friends, siblings or working partners.

What to do next with your composite chart

1. Read your own chart first. A composite makes more sense once you know what each of you brings.
2. Compare the two charts in synastry. That shows the exchange between you.
3. Then look at the composite Sun, Moon and Venus. Ask one question: does this sound like the two of us at our best?
4. Where it does, you have words for something you already knew. Where it does not, trust your experience over the chart.

A Compatibility Reading compares your birth chart with your partner's, calculated from both sets of exact birth data. It describes tendencies and never gives a score or a verdict.