Compatibility isn’t a score.
It’s a description.

Two charts, drawn from two exact moments, and the specific angles between them. No percentages, no verdict. Just what is actually there, named.

you

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                      What synastry actually is

                      Synastry is the comparison of two birth charts. Each chart is a map of the sky at one exact moment, and synastry measures the angles between them: your Venus against their Mars, your Moon against their Saturn, and so on. Those angles are the whole subject. They describe how two people meet, not whether they should.

                      Why there is no compatibility percentage

                      A number is easy to share and impossible to check. Reducing two charts to “87% compatible” throws away the only useful part, which is the specific contact that produced it. This tool names each dynamic and prints the aspect and orb it came from, so nothing is asserted that you cannot trace back to the chart.

                      What the reading covers

                      Five dynamics, each drawn from a real contact between the two charts: the pull (Venus and Mars), the friction (Mars and Saturn), the comfort (the Moon), the blind spot (Neptune), and the long game (Saturn). Where a pair has no such contact, we say that plainly instead of inventing one.

                      If you don’t know their birth time

                      You can still run it. Without a birth time the Moon has to be placed from a noon chart, and the Moon moves roughly thirteen degrees a day, which is enough to land it in the wrong sign. So we leave out anything that depends on it and mark what was left out, rather than quietly guessing and presenting the guess as fact.

                      Questions people ask

                      What is synastry in astrology?
                      Synastry is the comparison of two birth charts: it measures the angles between one person's planets and another's. Those angles, called aspects, describe how two charts meet, where they support each other, and where they grind. It is a description of a dynamic, not a verdict on a relationship.
                      Is there a compatibility percentage or score?
                      No, and deliberately not. A percentage flattens two whole charts into a single number that cannot be checked or acted on. This tool names specific contacts instead, and shows the exact aspect and orb each one came from, so you can see the reasoning rather than trust a figure.
                      Do you need exact birth times for compatibility?
                      Not to get a reading, but it changes what can honestly be said. Without a birth time the Moon can only be placed from a noon chart, and the Moon moves about thirteen degrees a day, which is enough to put it in the wrong sign. When a time is missing we leave those parts out and say so, rather than guessing.
                      Which placements matter most for compatibility?
                      Venus and Mars describe attraction and desire, the Moon describes what makes each person feel safe, and Saturn describes what holds a relationship in place over time. Sun signs alone are the least of it, which is why two people with the same signs can have entirely different relationships.
                      Are some zodiac signs incompatible?
                      No pair is ruled out by sign. A difficult angle between two charts is genuinely harder work, but it is also what keeps many long relationships awake. What matters is whether both people can name the pattern, which is what a reading is for.

                      By sign

                      The general shape of a pairing, before either birth time is known. Useful, and much blunter than the tool above.