Synastry Aspect Grid Calculator

A synastry aspect grid is a planet-by-planet matrix. One person's chart runs across the top, the other's down the side, and every cell holds the aspect between that pair of points, with the exact orb. It shows every inter-aspect between two charts at once, in one read, instead of a scrolling list.

That last part is the point. A list tells you Venus trines Mars and makes you hunt for the next line. The grid puts the whole relationship in your field of view, so the pattern shows up before the individual contacts do. Astrologers have built this by hand for decades. The calculator just draws it in a second and gets the orbs right.

Start with the axes. One person's planets run across the top, the other's down the side. Which person goes where is arbitrary, the grid reads the same both ways, so pick whoever you think of as person A and stay consistent. A filled cell means those two points make an aspect. Empty means they don't, at least not within orb.

Every filled cell carries the aspect glyph, the orb, and a color that sorts it harmonious or challenging at a glance. The orb is the number that does the work, and it's the first place people misread the grid. A contact at half a degree is a different animal from the same contact at six degrees. The tight one is loud and structural. The wide one is a background hum. Read every populated cell with equal weight and the grid will lie to you. Let your eye go tight-first.

Then there's the urge to count. Nine trines and four squares is not a relationship that is two-thirds good. Synastry doesn't tally. One tight square between the Moon and Saturn can define a bond more than a fistful of wide sextiles, because the Moon and Saturn carry more than whatever points those sextiles happen to connect.

Which planets, not how many. A Pluto or Uranus contact looks dramatic and people fixate on it, but the outer planets move slowly enough that a whole cohort born within a few years shares almost the same positions. Your partner's Venus on your Mars is personal. Your partner's Pluto on your Mars is half generational. Weight the personal planets and the angles first.

And read the grid as a whole, not cell by cell. Two charts will usually show a theme repeating: Saturn landing on three of your partner's personal points, or every Venus contact you make running tight. That repetition is the signal. A single cell is a sentence. The pattern across the grid is the paragraph.

Applying vs separating in synastry

Most synastry tools don't tell you whether an aspect is applying or separating. This one can show that when the speeds are available, and then leaves the call to you.

Here's the split. An applying aspect is still tightening toward exact. A separating one has already passed exact and is widening. In transit work that distinction is load-bearing, applying transits are the ones that haven't fully landed yet. In synastry it's contested. One camp reads applying contacts as the live, still-charging ones and separating contacts as already integrated. Another camp points out that both charts are frozen birth moments, neither planet is going anywhere, so the label is borrowed from a context where it fits better.

We don't pick a side for you. The calculator derives the state from each chart's planetary speeds and shows it where the math resolves. The angles and calculated points such as the North Node have no speed in this response, so those contacts stay blank rather than guessed. If you have never weighted applying versus separating before, the honest move is to notice it and keep reading.

Transparency first, because a grid is only as honest as the orbs behind it.

The grid plots the Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto, plus Chiron, the North Node, the Ascendant, and the Midheaven. Aspects are the five Ptolemaic ones: conjunction, sextile, square, trine, opposition. No minor aspects in the default view, they crowd the matrix and rarely change the read.

Orbs run tighter than you would use for a natal chart. A synastry contact has to be reasonably close to count, so the looser, wider hits get filtered out by the engine before they reach the grid. Every cell and every row in the contacts list carries its exact orb, in degrees and minutes, so nothing about the reading is hidden behind a rounded number. Positions are computed from ephemeris-backed sky data, not pulled from an interpretation table.

If you only have a minute with the grid, go to four pairings.

Sun and Moon contacts between the charts are the spine of the thing. The Sun on the other person's Moon, Moon on Moon, Sun on Sun: these are the day-to-day fit, whether the relationship feels like home or like work. Venus and Mars are the chemistry axis. Venus on Mars, the conjunction and the hard aspects most of all, is what people mean when they say two charts have heat.

Saturn is the one people flinch at and shouldn't skip. Saturn contacts to a partner's personal planets show where the relationship asks for commitment, structure, and sometimes weight. They're not bad. They're the difference between a spark and something that holds.

Then the nodes. North Node contacts, particularly to the Sun, Moon, Venus, or Mars, carry that sense of consequence, of the relationship meaning something beyond its parts.

Everything else on the grid is real, but those four pairings are where the character of the relationship usually lives. Read them first. If the nodal and Saturn contacts are what pull your eye, the karmic synastry calculator scores that layer specifically.

A score answers one question: how good is this, on a scale. The grid answers a different one: what is actually going on between these two charts. They're built for different jobs.

If you want the scored read, weighted and summarized, the compatibility calculator does that. This page deliberately doesn't. There's no number at the bottom, no verdict. The grid hands you the raw matrix and trusts you to read it, which is what you want once you've stopped asking whether a relationship is good and started asking how it works.

Pair it with the house overlays calculator to see where those aspects land, or the composite chart calculator when you want the relationship read as a single chart instead of a comparison.