Free Composite Chart Calculator
A composite chart merges two birth charts into a single chart of the relationship itself — its own Sun, Moon and Ascendant. Enter both sets of birth details, then ask our AI what your relationship is here to be.
No account, no sign-up · both charts are computed fresh and deleted when your session ends · the AI reads only those charts and never gives medical, legal or financial advice.
Ask AstroNoir About Your Composite
The composite is the relationship itself. Ask our AI up to three free questions — it reads both charts and your composite.
Your privacy. No account, no sign-up — you can enter test data and stay completely anonymous. Everything you enter is used only to compute your chart and to let the AI answer you during your visit, then automatically deleted when your session ends — we don't keep it, sell it, or tie it to your name. The AI reads only your freshly computed chart, never a stored profile, and never gives medical, legal or financial advice. The one and only thing we ever keep is fully anonymous: if our Birth Time Finder guesses your time and you choose to tell us it was wrong, we save that single correction — with no name, ever — to make our guessing better. Nothing else.
What a composite chart is
A composite chart is built from the midpoints between two people's planets — the exact halfway point between your Sun and theirs becomes the composite Sun, the midpoint of your two Moons becomes the composite Moon, and so on for every planet and angle. The result is a single chart that belongs to the relationship itself, not to either person: it describes the bond's character, its purpose and where it is heading, as though the connection were its own being with its own birth chart. Where synastry shows how two people affect each other, the composite shows what they become together. AstroNoir builds it from both birth charts with Swiss Ephemeris precision — the arc-second planetary data that professional astrologers rely on.
Synastry or composite — which should you use?
They answer different questions, and the deepest readings use both:
- Synastry compares your two separate charts — your planets to theirs. Use it to understand the chemistry between you: attraction, friction, where you click and where you clash. Run your synastry →
- Composite merges both charts into one new chart of the relationship as its own entity. Use it to understand what the relationship is — its purpose, its core character and where it is heading, independent of either of you.
A simple way to hold it: synastry is how the two of you behave toward each other; the composite is the third thing the two of you create together.
How to read your composite chart
Three points carry the heart of any composite — look at these first:
- Composite Sun — the core purpose and identity of the relationship: what it is fundamentally about, and where its shared vitality and direction point.
- Composite Moon — the emotional heart of the bond: how safe, nourished and understood the two of you feel together, and the mood the relationship lives in.
- Composite Ascendant — how the relationship appears to the outside world and how it first feels to step into. This one needs accurate birth times for both people.
From there, the composite houses show which areas of life the relationship activates, and the composite aspects show its inner ease and tension. Ask the AI below to walk you through any of it.