Free Birth Chart Compatibility Calculator

Discover your astrological compatibility with anyone using the same planet-by-planet birth chart engine that powers Signz. New to synastry? Read our synastry chart compatibility guide or our Sun sign compatibility guide, or our Moon sign compatibility guide. Curious how this compares to astrology on dating apps? See our Tinder Astrology Mode guide.

What This Calculator Measures

This calculator compares your full birth charts — all 12 chart points — using the same planet-by-planet, degree-by-degree scoring engine that powers Signz. Your Sun, Moon, Rising, and every planet are compared with real planetary aspects to reveal your compatibility dynamic.

The engine weighs your Identity placements (Sun, Moon, Rising) at 50% of the score, Chemistry placements (Mercury, Venus, Mars) at 40%, and Destiny and Outer placements at 5% each. Cross-planet bonds like Sun-Moon and Venus-Mars are scored bidirectionally, so the result is always symmetric.Learn how it works.

The 12 Chart Points

Sun

core identity and life purpose

Moon

emotions and inner needs

Rising

first impressions and vibe

Mercury

communication and thinking

Venus

love language and values

Mars

drive and passion

Jupiter

growth and beliefs

Saturn

commitment and discipline

North Node

karmic direction

Uranus

individuality and change

Neptune

dreams and imagination

Pluto

transformation and power

How Unknown Birth Time Is Handled

Your Rising sign requires an exact birth time to calculate. If you don’t know the birth time, check “I don’t know the birth time” and the engine will omit the Rising sign and rebalance the score without penalizing you. The remaining chart points are scored at their true weights — no artificial ceiling, no unfair penalty.

When you create a Signz account and add your birth time later, all 12 chart points — including Rising — snap into full calculation automatically.

Frequently Asked Questions

Is this birth chart compatibility calculator free?

Yes, completely free. You get a real compatibility score and a preview of your strongest connections immediately, and the full 12-point report is unlocked with just your email.

Do I need to know both birth times?

No. If you don’t know a birth time, check "I don’t know the birth time." The engine omits the Rising sign and rebalances the score without penalizing you.

Is my birth data saved?

No. Your birth details are processed transiently to calculate your natal chart and are not saved or persisted. They are sent to our astrology calculation service, then discarded.

What does the full report include?

The full report breaks down all 12 chart points — Sun, Moon, Rising, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, and North Node — with tier summaries, cross-planet bonds, and aspect explanations from the real scoring engine.

How accurate is astrology compatibility?

Astrology compatibility is a tool for self-reflection and exploring connections, not a scientific predictor of relationship success. Use it as one perspective among many.

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