What is actually between the two of you

What synastry actually is

Synastry is the old technique of laying two birth charts over one another and reading what touches what. Their Venus landing on your Moon. Your Mars squaring their Mercury. Their Saturn sitting on your Sun. Each contact describes a specific dynamic between two specific people, which is why it tells you something that comparing sun signs never can.

Twelve signs by twelve signs is one hundred and forty-four boxes, and every relationship that has ever existed is meant to fit in one of them. No astrologer worth the name has ever worked that way.

The tense angles are not the bad news

This is the part the internet gets most wrong. An overlay full of trines and sextiles describes a relationship that is comfortable and can be, honestly, a little inert. Nothing pushes. Nothing has to be resolved.

The hard angles are where relationships actually happen. A square between two charts is friction, and friction is what makes people develop. The long marriages are rarely the frictionless ones. They are the ones where two people worked out what the friction was asking of them.

Which is why are we compatible is the least useful question you can bring to a chart, and what is difficult between us, and what is it for is the most.

If you do not know their birth time

Most people do not, and it is worth being straight about what that costs. Without a birth time you lose the rising sign, all twelve houses, and the Moon's exact degree. This calculator computes from noon and then tells you which parts are approximate rather than printing a rising sign it cannot possibly know.

What survives is the Sun, Venus and Mars contacts, and those carry most of what a relationship reading is about. It is a real loss, not a fatal one.

Why there is no percentage

Because there is no such number. A compatibility score is the single most dishonest thing a tool like this can print, and people make real decisions on them. You get the contacts that are genuinely there and what each one tends to mean in a life. What you do with that is yours.