How sign compatibility works

Traditional sign compatibility comes from the angle between two signs. Signs of the same element (fire, earth, air or water) sit four signs apart and share a temperament, so they are the classic easy matches. Signs two apart pair complementary elements, fire with air and earth with water, and tend to be good friends. Signs three apart share a mode (cardinal, fixed or mutable) but not an element, which brings friction. Signs six apart are opposites: a strong pull and a lot to learn.

That gives every sign the same answer for everyone born under it. A birth chart is more specific: the calculator compares both people’s Sun, Moon, Venus, Mars and the rest at their exact degrees, which is why two couples with the same signs can get very different results.