Guides · Astrology compatibility

Synastry for dating: what it tells you, and what it doesn’t

Synastry is the astrological practice of comparing two birth charts. Used well, it is a conversation scaffold and an early filter. It is not a prophecy.

What synastry actually is

Your birth chart is a map of where the Sun, Moon and planets stood at the time and place you were born. Synastry lays one person’s chart over another’s and looks at the angles between their placements. Those angles are called aspects.

Two placements 0° apart (a conjunction), 60° (sextile) or 120° (trine) are usually read as flowing. Placements 90° (square) or 180° (opposition) apart are read as tense. Tense does not mean doomed; in most traditions it means friction that creates energy, and sometimes attraction.

What gets compared

• Sun — core identity and what energises someone.
• Moon — emotional needs and how someone feels safe.
• Venus — how someone shows and wants affection.
• Mars — drive, desire, and how someone handles conflict.
• Rising sign — first impressions. It needs an exact birth time, so it is the one placement you can skip.

This is why “Sun sign compatibility” is a thin shortcut. Your Sun sign is one placement out of several, and often not the one that shapes how a relationship feels day to day.

What it can genuinely help with

Used as a framework rather than a verdict, synastry gives two people something specific to talk about: “your Moon sits on my Venus, so I may feel unusually at ease with you,” or “our Mars placements clash, so we may need to learn each other’s conflict pace.” It can also point to likely friction early, in language that is easier to discuss than “you’re annoying.”

What it can’t tell you

Astrology is not a science, and there is no scientific evidence that birth charts predict whether a relationship will work. We say that plainly because it matters for how you use it.

Synastry cannot tell you whether you will be attracted to someone in person, whether you want the same things, how they behave when you disagree, or whether the logistics fit. Strong synastry will not rescue a mismatch on the basics: whether you want children, what each person is looking for, where you each live. Those basics usually decide a relationship before any planet does.

How MoonVibe uses synastry

MoonVibe calculates each person’s chart from their birth date and place, then scores the degree-based aspects between their Sun, Moon, Venus, Mars and rising sign, using the method published by Italian astrologer Ciro Discepolo. The result is one of four tiers (Wonderful, Harmonious, Promising, Complex) with a written explanation of what sits behind it.

Synastry is only one layer. MoonVibe also asks about the things charts can’t see, such as relationship intent, attachment style and whether you want children. Where both people have answered, a separate Premium readout compares them. See how to read a MoonVibe compatibility breakdown.

A sensible way to use it

1. Treat the tier as a reason to start a conversation, not a reason to stop one.
2. Sort out the basics (intent, children, location) early, whatever the chart says.
3. Pay attention to how someone actually behaves. That outweighs any placement.

Frequently asked questions

Keep reading

• How to read a compatibility breakdown