Free tool
Love Compatibility Calculator
Compare two birth charts the way a professional astrologer would. Astreya's free synastry engine looks at Sun, Moon, Venus, Mars and Ascendant contacts to show real chemistry — not another Sun-sign quiz.
- ✦ Full synastry between two natal charts
- ✦ Sun / Moon / Venus / Mars aspects
- ✦ Ascendant & house overlays
- ✦ Strengths and friction points
- ✦ Works for any relationship
- ✦ Instant, no signup required
What real love compatibility looks like
Sun signs alone say almost nothing about how two people actually feel together. Synastry — the branch of astrology that studies two charts side by side — looks at where each person's Moon lands in the other's chart, how Venus and Mars talk to each other, and which houses light up. Those are the signals that predict comfort, attraction and the kind of arguments a couple will have.
Astreya calculates both charts with Swiss-Ephemeris-grade precision and produces an honest reading: the aspects that flow, the ones that friction, and the practical advice on how to work with both.
Frequently asked questions
How does the love compatibility calculator work?
Astreya builds two natal charts and overlays them (synastry). It checks Sun/Moon/Venus/Mars aspects, the ascendant contacts and house overlays that classical astrology treats as the strongest indicators of chemistry, comfort and long-term fit.
Is it more than just Sun-sign matching?
Yes. Sun-sign matches are a party trick. Real synastry looks at Moon (emotion), Venus (love language), Mars (drive & attraction), Ascendants and the aspects between both charts.
What do I need from my partner?
Both people's date, time and city of birth. Time is important — Moon and Ascendant can shift signs within hours.
Can I compare with a friend or family member?
Absolutely. Synastry works for any relationship — romantic, platonic, family or business.
Do you store our birth data?
Only what's needed to compute the chart. We don't sell or share it.