Zodiac Compatibility Calculator
Compare two birth charts for an instant synastry love match. We blend your Sun, Moon and Venus signs — the placements that matter most in love — calculated privately in your browser.
What is synastry?
Synastry is the branch of astrology that compares two birth charts to understand a relationship. Rather than judging a couple on sun signs alone, it looks at how each person's planets interact — where you harmonise, where you spark and where you'll need to work. Your Moon signs show emotional compatibility, your Venus signs show how you each love, and your Sun signs show how your core identities fit.
Use the calculator above for a full two-chart reading, or browse the sign-by-sign guides below.
Compatibility by sign
Pick any pairing to read its full love, communication and long-term breakdown.
♈ Aries compatibility
♉ Taurus compatibility
♊ Gemini compatibility
♋ Cancer compatibility
♌ Leo compatibility
♍ Virgo compatibility
♎ Libra compatibility
♏ Scorpio compatibility
♐ Sagittarius compatibility
♑ Capricorn compatibility
♒ Aquarius compatibility
Frequently asked questions
What is a synastry / compatibility calculator?
Synastry is the astrology of relationships — it compares two people's birth charts to see how they interact. Our calculator computes both charts and scores your Sun (identity), Moon (emotional needs) and Venus (love style) compatibility instantly and free.
Is sun-sign compatibility accurate?
Sun-sign compatibility is a useful starting point, but Moon and Venus signs often matter more in love. That's why our calculator blends all three rather than relying on star signs alone.
Do I need exact birth times for compatibility?
For Sun and Venus comparisons, birth dates and places are enough. Exact birth times add Moon-sign precision and unlock rising-sign and house comparisons for a deeper reading.
Is the compatibility calculator free?
Completely free, with no sign-up. Both charts are calculated privately in your browser and nothing is stored.