Discover your cosmic compatibility. Calculate the astrological connection between two birth charts.
Synastry is the art of relationship astrology. By comparing two birth charts, synastry reveals the cosmic dynamics between two people - areas of harmony, attraction, challenge, and growth potential. This ancient practice helps us understand why we connect with certain people and how to navigate our relationships with greater awareness.
Our synastry calculator analyzes sun sign compatibility, elemental harmony, and key aspects between your charts to provide insights into romantic, friendship, and long-term relationship potential.
Synastry (from Greek syn = together + astron = star) is the comparative analysis of two natal charts to understand relationship dynamics. When two people interact, their planetary "signatures" create a unique chemical reaction—a third energy field that defines the relationship.
Unlike simple sun sign compatibility, synastry examines all planets in both charts: how your Venus relates to their Mars, how your Moon sits in their 7th House, whether Saturn creates the "glue" for longevity or restriction that suffocates.
Remember: synastry is a tool for understanding, not a verdict. The most challenging aspects often appear in the most transformative partnerships. Awareness turns potential friction into opportunities for growth.
Three different ways to analyze a relationship astrologically. Each serves a distinct purpose.
"You versus Me"
Overlays your planets onto their chart. Shows the direct impact each person has on the other— daily friction, attraction, and buttons pushed.
Best for: Sexual chemistry, emotional reciprocity
"The We Entity"
Midpoints between your planets create a new chart. Describes the relationship itself as a third entity with its own destiny and character.
Best for: Relationship purpose, public image
"The Relationship Birth"
Midpoint in time and space between both births. Creates a theoretical "birth chart" for the relationship that can be progressed and transited.
Best for: Predictive work, timing
Key insight: A couple may have harmonious synastry but a difficult composite—meaning they like each other but the relationship faces external obstacles. Conversely, challenging synastry with a strong composite suggests a difficult daily dynamic that nonetheless accomplishes great things.
Aspects are geometric angles between planets. In synastry, they define whether energy flows smoothly or creates friction. Friction isn't bad—it's necessary for passion and growth.
Not all planets carry equal weight. Sun, Moon, Venus, and Mars are the primary drivers of daily interaction. Saturn provides longevity. Pluto transforms.
When Person A's planets fall into Person B's houses, it reveals where in life the impact is felt. The House Person feels the Planet Person in that specific life domain.Note: Accurate house overlays require an exact birth time. Get your natal chart first to verify your house placements.
Planet person impacts House person's self-image and physical presence. Direct, visceral attraction.
Feeling "seen." Strong physical attraction.
Triggers deepest emotional security and childhood conditioning.
Feeling like family immediately. Strong cohabitation desire (Moon/Venus) or feeling invaded (Mars/Saturn/Pluto).
The overlay of dating, play, and procreation. Fun and sexual spark.
Makes House person feel alive and creative. Strong for dating; doesn't guarantee longevity alone.
The "Marriage" zone. House person views Planet person as ideal partner material.
Compulsion to commit. Sun, Moon, Venus here = classic marriage indicators.
Deep psychology, shared resources, and sexual merging. Feels fated.
Opens shadow side. Difficult to leave. Involves debt, secrets, or deep healing.
Stimulates the subconscious mind. Psychic link or past-life familiarity.
Projection of fantasy. Common in secret affairs or unrequited love.
The "orb" is how far from exact an aspect can be and still count. Tighter orbs = stronger effect.
8-10°
Sun & Moon
Widest orb—strong pull
5-7°
Mercury, Venus, Mars
Standard personal planet orb
3-5°
Saturn, Jupiter, Outer
Tighter to avoid generational noise
2-4°
ASC/DSC/MC/IC
Requires exact birth time
Beyond planets, these calculated points reveal karmic patterns, fated encounters, and soul contracts.
Contacts here are developmental—pushes the Node person toward their destiny.
Feels challenging but promotes necessary growth.
Indicates past-life connection. Instant familiarity: "I've known you forever."
Comfortable but can trap the couple in old patterns rather than evolving.
The "secondary Descendant." Represents fated encounters beyond your control.
Personal planet conjunct Vertex = life-altering meeting with "before and after" quality.
The marriage asteroid. Specific needs in a committed partner (distinct from Venus romance).
Juno conjunct Sun/Jupiter/Ascendant = potent marriage indicator. Partner fits "spouse blueprint."
The Wounded Healer. Deepest spiritual wound and capacity for healing.
Venus/Jupiter to Chiron soothes old pain. Mars/Saturn to Chiron re-traumatizes. Painful but offers integration.
Explore your special points:
Soulmates bring ease and support. Twin Flames bring intensity and ego destruction. Most people want a soulmate—twin flames are for spiritual awakening, not domestic bliss.
Ease, mutual understanding, support, and feeling "home."
Mirroring, intensity, runner/chaser dynamics, ego destruction.
A high-scoring chart needs both chemistry (Venus/Mars/Uranus) and structure (Saturn/Juno). Missing either creates imbalance.
High Venus/Mars/Uranus but low Saturn = passionate fling that burns out quickly. "Amazing sex but they never call."
High Saturn/Juno but low Venus/Mars = stable, dutiful "roommate marriage." "We respect each other but the spark died."
Strong Sun-Moon contacts (core understanding) + Venus-Mars aspects (physical glue) + Saturn contacts (structural commitment) = sustainable, passionate long-term partnership.
No single aspect guarantees failure, but these configurations require maturity to manage safely. Awareness is the antidote.
Mars-Pluto Square/Opposition
Power struggle of epic proportions. Can indicate domination or physical abuse without maturity.
Saturn-Moon Hard Aspects
Saturn creates cold, critical environment. Moon person feels unsafe expressing feelings.
Neptune-Mercury/Venus Hard
High probability of deception or delusion. May fall in love with fantasy version of partner.
Uranus-Venus Hard Aspects
Extreme instability. Relationship is on-again/off-again, preventing real security.
Synastry is the art of relationship astrology. It compares two birth charts by analyzing how the planets in one chart aspect (form angles to) the planets in another. This reveals areas of harmony, attraction, challenge, and growth potential between two people.
For basic Sun sign synastry, only birth dates are needed. However, exact birth times allow analysis of house overlays, rising sign contacts, and accurate Moon placement— which are crucial for deeper compatibility insights.
No. Squares and oppositions create friction, but friction generates passion and growth. Many long-term marriages have Venus-Mars squares. The key is awareness and willingness to work with the energy constructively. Trines can actually become complacent.
Sun-Moon contacts are the gold standard for compatibility. Venus-Mars aspects indicate sexual chemistry. Saturn contacts provide the "glue" for longevity. The ideal partnership has a balance of all three.
Synastry reveals potential dynamics and challenges—it doesn't dictate outcomes. Free will, maturity, and communication matter more than any aspect. Use synastry as a tool for understanding, not as a verdict on your relationship's viability.
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