Composite chart calculator
One chart for the two of you. See what you make together.
Both birth times give the Moon and the angles; without them the result is marked approximate.
A chart for the two of you
The calculator compares every planet in one chart with every planet in the other. The score is a reading aid, not a verdict on the relationship.
A composite chart treats a relationship as its own chart. Each planet is placed at the midpoint between the same planet in both birth charts, and the result describes the shared weather: what the relationship is like from the inside, independent of either person's individual chart.
How this is calculated
The position
Each pair of planets is averaged on the shorter arc of the zodiac, so the result is the point between them rather than a simple arithmetic mean.
The zodiac
The Ascendant and Midheaven are averaged in the same way when both birth times are known. Without both times, the composite has no angles.
The clock
The composite is read alongside synastry. Synastry shows the contact between two people; the composite shows the thing they make together.
Questions
What does a composite Sun sign mean?
It describes the purpose or center of gravity of the relationship. It is not the same as either person's Sun sign, and it often describes what the pair is trying to become together.
Do we need exact birth times for a composite?
For the planets, no. For the composite Ascendant and Midheaven, yes. Without both times the calculator still gives the planetary midpoints and states that the angles are unavailable.
Is the composite chart more accurate than synastry?
Neither is more accurate. They are different lenses. Use synastry for the dynamic between two people and the composite for the shared field they create.