Compare two birth charts

Why Sun signs are only a rough start

Sun-sign compatibility compares one placement out of many. Your Sun describes your core identity, but your Moon, Venus, Mars and other planets shape how you feel, love, argue and spend time together. That is why two people with supposedly mismatched Sun signs often get along very well.

Birth chart compatibility, also called synastry, compares both whole charts. It looks at where each person's planets actually were on the day they were born and how those positions relate to each other.

How two charts are compared

Astrologers look for aspects between the two charts. An aspect is a meaningful angle between two planets. When your Venus sits in the same place as their Mars, that is a conjunction, and the two energies blend. A trine or sextile usually feels easy and supportive. A square or opposition brings friction, which can create attraction and growth as well as tension.

The closer the angle is to exact, the stronger the contact tends to feel. This tool lists the strongest contacts between your two charts and explains each one in plain language.

The contacts that matter most

Contacts between the Sun and Moon speak to how well your core selves and emotional needs fit. The Moon in particular shows whether you feel at home with each other day to day. Venus and Mars describe affection, attraction and desire. Mercury shows how easily you talk and solve problems together. Saturn contacts often describe staying power and commitment, and sometimes a sense of weight or duty.

No single contact makes or breaks a relationship. The overall pattern matters more than any one aspect.

The 7th house and why birth times help

In astrology, the 7th house is the house of partnership. It sits directly opposite your Rising sign and describes what you look for in a close partner and what you tend to learn through one-on-one relationships. Because houses depend on the exact time of birth, the 7th house and the Rising sign need a birth time to be read.

If one or both birth times are unknown, the comparison still works with the planets, but Rising signs and houses are left out, and the Moon only counts when its sign is certain. To see your own 7th house, try the free birth chart reading on this site.

Using compatibility well

No pairing is doomed and no pairing is guaranteed. A comparison shows where things may flow easily and where you may need more patience, but relationships are built through the choices two people make. Talking openly about what the comparison shows, the easy parts and the harder ones, is often more valuable than the reading itself. Please only compare someone's chart when they are comfortable sharing their birth details.

Questions