There are thousands of compatibility tests online, and most generate a random percentage for the sake of a pretty number. Here's the honest version: what two birth dates can tell you, what they can't, and what a defensible calculation looks like.
Level 1: Sun signs
Day and month give the zodiac signs — already a meaningful layer: elements and modality describe the couple's default dynamic. Fire and air accelerate each other, earth gives water a shape, two fixed signs clash in stubbornness. Check your pair in the all-78-combinations table: Aries and Leo, Cancer and Capricorn, Gemini and Libra and the rest.
Level 2: the full date
The full date adds the Moon (emotional fit), Venus and Mars (love language and temperament) — planetary positions computed astronomically from ephemerides. That's birth-date synastry: comparing two charts layer by layer — feelings, money, daily life, crisis points.
What the percentage really means
- An honest score measures the default ease of contact, not the couple's verdict: 60% isn't "worse" than 85% — it's a different dynamic with different tasks.
- A low Sun-sign score is often offset by a strong Moon or Venus–Mars link — which is why a full-date test beats a sign-only test.
- No calculation accounts for choices, experience and the work a couple puts in: astrology describes starting conditions, not the ending.
Full compatibility from two birth dates
AstroOrbi builds both charts with Swiss Ephemeris and reads the pair across every layer: love, money, daily life, crisis points — with a rating and honest wording.
FAQ
Can I test compatibility with just birth dates, no birth times?
Yes: Sun signs, the Moon (with a small margin on boundary days), Venus and Mars all compute from the date. Birth time adds houses and the Ascendant — a refinement, not a requirement.
What's a good compatibility percentage?
Above 70% means easy contact by default, 50–70% a workable pair with growth zones, below 50% a dynamic that needs awareness. Either way it's starting conditions, not a sentence.
Why do different tests give different percentages?
Most tests only use Sun signs or simply generate a number. Full-date calculations based on real planetary positions agree with each other far better.