A composite chart describes a relationship as if it were a person in its own right. Instead of comparing two charts, it merges them: this calculator takes the midpoint of each pair of planets from two birth charts and builds a single composite chart, whose signs describe the identity and tone of the partnership itself.
How a Composite Chart Is Made
For every planet, the calculator finds the midpoint between its position in the first chart and the second, and places that midpoint in a sign. The result is one blended chart that belongs to the couple rather than to either individual. Its composite Sun shows the core purpose of the bond, and its composite Moon the emotional tone the two share.
Composite Versus Synastry
Synastry and the composite chart answer different questions. Synastry asks how two people affect each other, planet to planet, while the composite asks what the relationship itself is like as a single thing. Many astrologers read both: synastry for the chemistry between the partners, and the composite for the character and direction of the union they form together.
Reading the Composite
Start with the composite Sun and Moon for the heart and feeling of the relationship, then look at composite Venus and Mars for affection and drive. The chart describes the relationship's nature, not a verdict on it, and is best read as a portrait to reflect on. For the most accurate result, include both birth times and places.
Building a Composite Chart
Add both birth dates, with times and timezones where you have them, then press Calculate. Instead of comparing two charts, the tool blends them into a single midpoint composite that stands for the relationship itself. You'll see the composite planets and their signs, which describe the character of the partnership as a third thing the two of you create.
The Midpoint Method
A composite chart isn't either person's chart, it's the mathematical middle of the two. The tool takes each pair of matching planets and finds the midpoint between them, so the composite Sun sits halfway between your Sun and your partner's, and the same goes for the Moon, Venus and the rest. Those midpoints are then read as a single chart that stands for the relationship as its own entity rather than for either individual.
Why Birth Times Help
The composite Moon, Ascendant and houses lean on both birth times, since they come from fast-moving points in each person's chart. With both times the midpoint chart is exact; without them the slower composite planets still read well, but the angles and the Moon are approximate. If you have both times to hand, the composite picture of the partnership comes out sharper. If only one time is known, you can still read the composite planets and simply hold the angles loosely.
Composite Chart Questions
What is a composite chart?
A composite chart is a single chart built from the midpoints of two people's planets. It describes the relationship itself as its own entity, rather than comparing the two individuals.
How is it different from synastry?
Synastry compares the two charts to study how the partners affect each other. The composite merges them into one chart to describe the character and purpose of the relationship as a whole.
What do the composite Sun and Moon mean?
The composite Sun shows the core identity and purpose of the relationship, and the composite Moon shows its shared emotional tone. They are the first points to read in a composite chart.
Positions are computed with the Swiss Ephemeris. Astrological interpretations are traditional and are offered for reflection, not as guaranteed predictions.
More to explore
There is plenty more to try in this tradition: Solar Return Calculator, Ashtakavarga Calculator, Lal Kitab Calculator and Kp Astrology Calculator. Each astrology calculator highlights something the others might not, so it pays to look around a little. Browse them all on the astrology calculators page, or see the complete calculator list.