Free Synastry Chart Calculator
Tell us who they are — partner, parent, friend, coworker — and what you want to understand. The reading reads the right way for the relationship you actually have, not a generic romance read.
What is synastry?
Synastry overlays two birth charts to map the dynamics between two people. Each person's planets form aspects with the other's — conjunctions, squares, trines — revealing what each person activates in the other.
Synthesis runs synastry in both Tropical and True Sidereal systems, then layers numerology and Chinese zodiac as weighted inputs. Multiple instruments, one connection. The goal isn't to score compatibility — it's to identify the dominant relational pattern.
What makes this reading different
Toned for the relationship you actually have
Every reading is shaped by who they are to you and what you want to understand. A reading for your mother reads nothing like one for a new partner. Pick the relationship type, the questions you care about, and add a personal note — the AI uses all three to set tone, focus, and register.
Every chart claim is fact-checked
Aspects, orbs, degrees, geometric patterns, and stellium claims are automatically verified against the actual computed chart before delivery. Invented aspects get softened. Fabricated scenarios — clock times, brand names, weekday inventions — get stripped. The reading you receive only asserts what the placements actually support.
Synastry readings are generated by artificial intelligence for entertainment and self-reflection purposes only. They are not a substitute for professional relationship counseling.
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Questions
What is a synastry chart?
A synastry chart overlays two birth charts to analyze relationship dynamics. It shows how one person's planets aspect another's, revealing areas of harmony, tension, and growth between two people.
How is synastry different from a composite chart?
Synastry compares two separate charts side by side, showing how each person affects the other. A composite chart merges both charts into one, representing the relationship itself as its own entity.
Do I need an exact birth time for synastry?
Birth time improves accuracy — especially for Rising sign and house placements. Without it, the core planet-to-planet aspects (Sun, Moon, Venus, Mars) are still meaningful.
What systems does Synthesis use for synastry?
Synthesis calculates synastry in both Tropical and True Sidereal systems, then layers numerology and Chinese zodiac as weighted inputs. Multiple instruments, one connection.
How does Synthesis compare to other synastry calculators?
Most free synastry calculators show one zodiac system (usually Tropical) and a single 'compatibility score'. Synthesis computes synastry in Tropical and True Sidereal at the same time, scores the connection across four dimensions (overall, romantic, communication, stability), and frames the analysis as a pattern of tendency rather than a forecast. The free overview shows the cross-chart aspects; a paid reading ($28 one-time) provides a written multi-system analysis.
Is Synthesis synastry free?
The synastry overview — cross-chart aspect grid, four-dimension scores in both Tropical and Sidereal — is free. The full written synastry reading is $28 one-time and includes a PDF analysis grounded in pattern language, not prediction.