Zodiac Compatibility

Enter the first person's birth details.

Person A->Person B->Results

Free chart generation. No signup required.

This compares both full natal charts, not just sun signs, so the results reflect emotional fit, chemistry, and friction points.

What Is a Synastry Chart?

The real science behind astrological compatibility.

300+

Data Points Analyzed

11

Planetary Bodies Compared

50+

Aspect Combinations

More Than Just Sun Sign Matching

A synastry chart overlays two people's birth charts to reveal how their planetary energies interact. Unlike simple zodiac sign matching — which only considers the Sun and covers roughly 15% of the picture — synastry examines every planet, house, and aspect between both charts.

Why Full Chart Analysis Matters

Two people with “incompatible” Sun signs can share deeply harmonious Moon, Venus, or Ascendant connections that create an unshakable bond. Conversely, matching Sun signs might mask challenging Mars or Saturn cross-aspects. Synastry captures the full story that sun sign columns miss entirely.

The 7 Planets That Shape Your Relationship

Each planet governs a different dimension of how two people connect.

Sun

Core Identity

Shows how your fundamental identities interact. Strong Sun contacts mean you naturally understand each other’s goals, values, and sense of self.

Moon

Emotional Safety

Reveals how emotionally safe you feel together. Moon aspects determine whether you instinctively nurture each other or trigger insecurity.

Venus

Love Language

Governs how you express affection and what you find attractive. Venus contacts show whether your love languages naturally align or need translation.

Mars

Passion & Drive

Controls physical chemistry and how you handle conflict. Mars aspects reveal whether disagreements fuel growth or destructive patterns.

Mercury

Communication

Shapes how you think and talk together. Mercury contacts determine whether conversations flow easily or require extra effort to bridge different mental styles.

Saturn

Commitment & Stability

The glue that holds relationships together long-term. Saturn aspects show where you build structure, but also where you might feel restricted.

Jupiter

Growth & Expansion

Where you help each other grow. Jupiter contacts bring optimism, generosity, and shared adventures. It’s the planet that makes the relationship feel like it’s expanding your world.

Synastry Aspects Explained

Aspects are the angular relationships between planets in two charts. They are the building blocks of compatibility.

Trine (120°)

The easiest flow of energy between two charts. Trines create natural understanding and effortless support. Venus trine Moon, for example, means emotional warmth flows naturally between you.

Venus △ Moon = emotional ease and natural affection

Sextile (60°)

A gentle, cooperative aspect that opens doors when you make an effort. Sextiles suggest compatible energies that blossom with a little initiative from both sides.

Mercury ✱ Jupiter = stimulating conversations and shared curiosity

Harmonious aspects feel easy but still need conscious effort to fully activate their potential.

How AI-Powered Compatibility Analysis Works

From birth data to personalized insight in under 30 seconds.

01

Enter Birth Details

Provide the birth date, time, and location for both people. If birth time is unknown, ChartNova uses noon as a default and marks house positions as approximate.

02

Astronomical Calculation

Our engine computes exact planetary positions, house cusps, and all cross-aspects between both charts using professional-grade astronomical data accurate to sub-arcsecond precision.

03

AI Synthesizes Your Reading

Unlike template-based reports, our AI analyzes the entire chart holistically — identifying patterns, themes, and nuances that a simple aspect list cannot capture. Your reading is delivered in seconds, not days.

Instant delivery, not 24-hour waits

Traditional compatibility reports cost $25+ and take hours or days to receive. ChartNova delivers a complete AI-powered reading in seconds — with the same astronomical precision.

Synastry Chart vs. Composite Chart

Two different lenses for understanding a relationship.

Synastry ChartComposite Chart
What it showsHow two people interact with each otherThe relationship as its own entity
MethodOverlays both birth charts side by sideCalculates midpoints of both charts into one
Best forUnderstanding attraction, friction, and dynamicsUnderstanding the relationship’s purpose and themes
RevealsWhat each person brings to the tableWhat the relationship feels like as a unit
When to useEarly stages, evaluating compatibilityLong-term partnerships, understanding shared goals

For the most complete picture, astrologers recommend examining both. Start with synastry to understand the dynamic between you, then use a composite chart to explore where the relationship itself is headed.

Ready to Discover Your Compatibility?

Enter both birth details above and get your full synastry chart in seconds. Free, no signup required.

Not Just for Lovers

Synastry works for any relationship where two people interact.

Romantic Partners

Explore emotional compatibility, physical chemistry, communication style, and long-term potential. See where you naturally click and where growth is needed.

Business Partners

Analyze Mercury and Saturn cross-aspects to understand communication and accountability dynamics. Discover whether your working styles complement or clash.

Family & Friends

Understand Moon and Jupiter connections that shape emotional bonds, generosity, and mutual support. Helpful for navigating family dynamics or deepening friendships.

Do You Need Exact Birth Times?

Accurate birth times improve the reading, but you can still get meaningful results without them.

With Birth Time

  • Precise house placements show where each planet's energy plays out
  • Accurate Ascendant reveals first-impression chemistry
  • Moon position is exact, refining emotional compatibility
  • Full 100% of available data points are analyzed

Without Birth Time

  • Planetary signs and cross-aspects are still fully accurate
  • House placements are marked as approximate (noon default)
  • Moon position may be off by up to 6 degrees
  • Still captures ~80% of available compatibility data

Tip: Check your birth certificate, hospital records, or ask a parent for your exact birth time.

FAQ

Everything About Synastry & Compatibility

What is a synastry chart?
A synastry chart is a comparison of two people’s birth charts, overlaid to reveal how their planetary energies interact. By examining the angular relationships (aspects) between one person’s planets and the other’s, synastry identifies areas of natural harmony, attraction, potential friction, and growth within the relationship.
How accurate is synastry?
The astronomical calculations behind synastry are extremely precise — ChartNova uses professional-grade data accurate to sub-arcsecond precision. The interpretive value depends on having accurate birth data. With exact birth times for both people, synastry provides the most complete picture. Even without birth times, planetary sign positions and major cross-aspects remain fully accurate.
Do I need my exact birth time for a synastry reading?
Exact birth times produce the most accurate reading — especially for house placements, the Ascendant, and the Moon’s precise position. Without a birth time, ChartNova defaults to noon and marks house-based results as approximate. You still get accurate planetary signs and cross-aspects, which represent roughly 80% of the compatibility picture.
What is the difference between synastry and a composite chart?
Synastry overlays two separate birth charts to show how two individuals interact with each other — the push and pull of the relationship dynamic. A composite chart calculates the midpoints of both charts to create a single chart representing the relationship itself as an entity. Think of synastry as "how we relate to each other" and the composite as "what our relationship is about."
What are the most important planets in compatibility?
The personal planets carry the most weight: Sun (identity alignment), Moon (emotional safety), Venus (love language and affection), Mars (physical chemistry and conflict style), and Mercury (communication). Saturn aspects are important for long-term commitment potential, and Jupiter aspects show where you help each other grow.
What are the best synastry aspects for love?
Some of the most favorable aspects for romantic relationships include Venus conjunct or trine Mars (strong physical and romantic chemistry), Moon trine Moon (emotional harmony), Sun conjunct Moon (deep mutual understanding), and Venus trine Jupiter (generosity and joy in the relationship). However, a healthy mix of challenging aspects keeps the relationship dynamic and growing.
Can two "incompatible" zodiac signs have a successful relationship?
Absolutely. Sun sign compatibility is just one small piece of the puzzle. Two people with traditionally "incompatible" Sun signs — like Aries and Cancer — might have beautifully harmonious Moon, Venus, or Ascendant connections. Real compatibility is determined by the full chart comparison, which is exactly what synastry provides.
How is AI used in the compatibility reading?
ChartNova’s AI analyzes the complete synastry data — all planetary positions, house placements, and cross-aspects between both charts. Rather than generating generic template text, the AI identifies patterns and themes across the entire chart to produce a personalized reading covering attraction, communication, emotional fit, challenges, and long-term potential.
What does ChartNova’s synastry reading include?
The free calculation includes a complete synastry chart with all planetary positions, house placements, and cross-aspects for both people, plus insight cards for strengths, communication, attraction, and growth areas. The AI-powered reading (Pro) adds a deep personalized interpretation covering relationship dynamics, emotional patterns, and actionable guidance.
Is my birth data kept private?
Yes. Your birth data is used solely for chart calculations and is never shared with third parties. Free charts are calculated in your browser session and are not stored on our servers. Paid reports are saved to your account so you can access them anytime, but your personal data remains private and encrypted.