Compatibility calculator

It is a starting point, not a conclusion. Your Sun is one factor out of roughly forty in a chart. It describes broad temperament well and says very little about the specific chemistry between two people — for that you want a synastry chart, which uses both charts in full.

It is a weighted blend of four things: how your elements interact, how your modalities interact, the angular distance between your two signs, and whether you share a ruling planet. The same pair always produces the same number — nothing is randomised.

Signs of the same element usually understand each other fastest, and opposite signs usually generate the most charge. Neither guarantees anything. Difficult pairings are extremely common in long relationships; they just require the differences to be spoken about rather than assumed.

There is no such thing as being between two signs; the Sun is in exactly one at any moment. But sign changes happen at a specific time of day, so if you were born on a boundary date, use the birth chart calculator with your birth time to be certain.