Every couple knows the phenomenon, even if nobody has named it. Two people who each love a party somehow become, together, a pair who are home by nine with tea. Two shy people become, together, the pair who organise every gathering among their friends. The relationship has a character of its own, and it is not simply the sum of the two characters in it.

The composite chart is astrology's attempt to draw that character. It builds one chart out of two, and reads that chart as if it belonged to a third thing: the relationship itself, rather than either of the people in it.

How a composite is built

The method is simple. For each planet, take its position in one chart and its position in the other, and find the midpoint between them. Your Sun and theirs make a composite Sun, your Moon and theirs a composite Moon, and so on through every planet and point.

Suppose one person has the Sun at 10 degrees of Aries and the other at 10 degrees of Gemini. The midpoint is 10 degrees of Taurus, so the composite Sun is in Taurus, a sign neither of them has the Sun in. That is not an error. It is the whole idea: the relationship can be steadier, or more restless, or more private than either partner on their own.

The composite Ascendant is found in the same way, and the composite houses are then drawn from it as twelve equal divisions. That detail matters, and we will come back to it.

An abstraction, and a useful one

An honest reading of a composite starts by saying what it is not. No sky ever looked like a composite chart. It has no moment and no place: there was never a day when the planets stood at those midpoints over a spot on the map. That is why it cannot have a birthday, and why its houses are equal slices from a midpoint Ascendant rather than the houses of a real horizon.

None of that makes it useless. Astrologers have read composites for about fifty years because the readings keep matching the couples. But it explains why there is a second relationship chart, the Davison chart, which is cast for the real midpoint in time and space between two births, and which is the better chart to follow through time. The two are companions rather than rivals: the composite is usually nearer to how a relationship feels, the Davison nearer to its timing.

Reading the composite: Sun, Moon, Ascendant

Read the composite Sun first. It says what the relationship is for: the thing the two of you keep doing together, whether or not you ever named it. A composite Sun in Capricorn is often a relationship that builds something, a business, a household, a plan with stages. A composite Sun in Sagittarius tends to be a relationship that travels, studies, argues about ideas, or at least owns a great many maps.

Then the composite Moon, which is how the relationship feels from inside: what makes it feel safe, and what unsettles it. A composite Moon in Cancer wants a home base and regular meals. A composite Moon in Aquarius needs room, and may be at its best when both people have their own projects to talk about at dinner.

Then the composite Ascendant, which is how the relationship looks to everyone else. It is often surprisingly different from how it feels. A pair with a calm, reserved composite Ascendant and a fiery composite Moon will be described by their friends as "so peaceful together", and will smile politely at that, having argued about the route all the way there.

The aspects belong to the relationship

The aspects inside a composite are not either person's aspects. They belong to the pair. A composite Venus square Saturn describes an affection that keeps meeting a limit: time, duty, distance, money. Both people will usually recognise it, even if neither has that aspect in their own chart.

This is the part of the composite that works better than its construction has any right to. A composite Mars conjunct Jupiter is a pair that takes on too much together and usually manages it. A composite Moon opposite Uranus is a pair whose emotional weather changes fast, and who may do best when they stop expecting it not to.

What our report shows

Our composite chart report reads the relationship in two runs of question and answer cards: first the aspects between the composite planets, then the composite planets in their signs and houses, with the Ascendant and Midheaven among them. Above each run, a button asks the AI astrologer to synthesise the run as a whole in about 400 words, built only from the placements on the page.

Below the readings are the composite chart wheel and the synastry wheel of the two birth charts, the aspect grids, the most important astrological elements between the two of you, and the full list of planet positions and aspects. A section called Areas of Mutual Attraction is an AI analysis of where the connection is strongest: emotional, romantic, spiritual, intellectual and professional. It works for any pair, a couple, two friends, two business partners, a parent and a grown child.

The site also has articles on individual composite placements, such as the composite Sun, the composite Moon and the composite Ascendant, if you want to read one of them in depth.

Birth times, and why they matter more here

The planets are fine without birth times, so the composite Sun, Mercury, Venus and Mars can be trusted. The composite Moon can be a few degrees out, because the Moon moves fast. The composite Ascendant and the houses need both times.

And in a composite, the Ascendant matters more than usual, because every house is measured from it. One unknown time therefore costs more in a composite than in a single birth chart. With a time missing, read the planets and their aspects, and treat the houses as missing rather than approximate.

Beside the synastry, not instead of it

Synastry and the composite answer different questions. Synastry keeps two people separate and says how each one lands on the other. The composite merges them and says what the two of them together become. Where the two readings agree, you can rely on what you are seeing. Where they disagree, the interesting question is usually which of the two the pair actually live in.

And a composite describes a relationship; it does not grade one. There is no compatibility score in our report, because a chart cannot tell two people whether to stay together. It can tell them what they will keep meeting, which is something they can work with.

When you are ready, cast the composite chart of a relationship here, and then read it beside the synastry of the same two people.

Frequently asked questions

What is a composite chart?
One chart built from the midpoints of two birth charts, read as the chart of the relationship rather than of either person. Your Sun and theirs make a composite Sun, and so on through both charts.

Composite or Davison chart?
A composite is an average and has no moment; a Davison is cast for the midpoint in time and space between two births, so it is the chart of something that really happened. Read both: the composite is usually nearer to the feel of a relationship, the Davison nearer to its timing.

Can a composite chart be transited?
It is commonly done, and this site offers it as the relationship forecast. Keep in mind that the composite houses are equal slices from a midpoint Ascendant, so a transit through a composite house means less than the same transit through a house of a Davison chart.

Do we both need a known birth time?
For the planets, no. For an exact composite Moon, and for the Ascendant and the houses at all, yes. Here the Ascendant matters more than usual, because every house in the chart is measured from it.

Is a composite chart the same as compatibility?
No. It describes what a relationship is like, not how good a match two people are. No compatibility score has ever held up well against real couples, and our report does not pretend otherwise.