What is a square?
It is the right angle: 90 degrees between two planets, a quarter of the wheel. Both are always in signs of the same mode — two cardinal, two fixed or two mutable — and in elements that do not go together: fire with water, earth with air.
An aspect is the distance between two planets measured on the wheel of the zodiac. When that distance falls close to an angle the tradition recognises, the two are said to form an aspect — and that is what links one part of the chart to another. The whole logic is in what an aspect is.
How common the square is
I measured 200,000 charts drawn at random between 1930 and 2025, with the same orbs this site uses to cast charts and with the engine’s own rule: each pair of planets forms one one aspect, the tightest one.
| Aspect | Angle | Average per chart | Charts that have at least one | Of the five major ones |
|---|---|---|---|---|
| Square | 90° | 2.90 | 93.5% | 23.4% |
| Sextile | 60° | 2.82 | 94.1% | 22.8% |
| Trine | 120° | 2.68 | 92.9% | 21.6% |
| Conjunction | 0° | 2.47 | 93.9% | 19.9% |
| Opposition | 180° | 1.52 | 73.0% | 12.3% |
| Quincunx | 150° | 0.93 | 58.2% | — |
It is the most frequent of the five, at 23.4% — and it wins for two reasons put together. Ninety degrees is one of the angles that have two places on the wheel, one on either side, and its orb is generous: eight degrees when the Sun or the Moon is involved. The sextile has the same two places and a narrower orb, and that is why it comes just behind.
And there is a number the table shows that almost no astrology text says out loud: 93.5% of charts have at least one square. Having one distinguishes almost nobody. What distinguishes is WHICH planets it links, and which houses they are in.
How the square feels
The square rubs, and the rubbing builds. It is the aspect that gives no peace: the two planets want the same intensity by routes that do not fit together. Unlike the opposition, it is not seen from outside — it is felt from within, as restlessness with no address. It is also the aspect that turns up most in the biography of people who built something: what does not rub asks for no work.
The limit is worth saying: these are tendencies, not a verdict. An aspect describes how two functions of the chart talk to each other — it does not foretell events, diagnoses nobody and decides nothing for you.
Four squares that show up a lot
The aspect on its own says almost nothing: what gives it a subject are the two planets. These four pairs are among the most common, and they show how the same geometry changes face:
| The pair | How it usually shows up |
|---|---|
| Sun–Moon | born on a first or last quarter Moon: identity and need make demands of each other |
| Moon–Mars | emotion comes out hot and fast; it usually looks like a short fuse that burns out quickly |
| Venus–Saturn | affection comes with a condition, and the person usually thinks she has to earn it |
| Sun–Saturn | authority makes its demands early; it is the pair that shows up most in those who grew up too soon |
Notice that the angle is the same in all four and the subject is completely different. That is why "I have a square" is not a reading — it is the start of one.
The pairs that never form a square
Four pairs never form a square. Mercury does not reach 27.8° from the Sun and Venus does not pass 47.2°, so neither of them reaches 90 degrees — and between themselves they reach at most 73.8°. The fourth is Neptune with Pluto, which spent the century between 42.6° and 65.3°. Any site showing "Sun square Venus" did not calculate the sky.
This is not a rule of one school: it is the orbits of the planets. And it is a useful check at home — if a site shows one of those pairs with this aspect, it is not calculating the sky.
The orb decides whether it counts
Two planets almost never fall on the exact angle. The orb is the leeway allowed: how far off the angle the aspect can be and still count. And it does not belong to the aspect alone — it depends on who forms it.
This site uses a wider orb for the Sun and the Moon, a narrower one for the outer planets, and takes the average of the two. Measured across the same 200,000 charts: when a square happens, the average distance to the exact angle is 3.22°. That is, the tight aspect is far more common than the one on the edge — and your chart shows the exact distance of each, instead of only the name.
See the squares in your chart — the chart is free and comes out at once, with date, time and city. It lists every aspect with the two planets, the orb and the exact distance. Generate my chart for free.
The square in your chart
The question that matters is not how many you have: it is where they fall. An aspect between two planets in the 10th house speaks of work and reputation; the same aspect between the same planets in the 4th speaks of home and family. The house depends on the hour and city of birth, and it is what turns geometry into a reading.
The two texts that carry on from here are what an astrological house is, which explains the twelve areas, and what the birth chart is, which puts the whole picture together.
Frequently asked questions about the square
Is the square the worst aspect?
No, and the reputation comes from an old reading that treated tension as a flaw. The square describes friction between two functions that demand of each other — which is uncomfortable and is also what makes someone develop something. A chart with no square is not an easy chart: it is a chart with no engine. And they exist, but they are few: 6.5% of charts have none.
How many squares does a chart usually have?
On average 2.90, measured across 200,000 charts drawn at random between 1930 and 2025 with the orbs this site uses. And 93.5% of charts have at least one — which means that having one distinguishes almost nobody; what distinguishes is WHICH planets it joins.
What is the orb of the square?
It depends on the two planets, not on the aspect alone. This site uses a wider orb for the Sun and the Moon and a narrower one for the outer planets, and takes the average of the two. When a square actually happens, the average distance to the exact angle is 3.22° — well inside the limit, because a tight aspect is more common than one on the edge.
Does the square show up in everyone’s chart?
No. 93.5% of charts have at least one, so 6.5% have none — and that is real information about the person, not a flaw in the calculation.
Questions for people just starting out
The square in brief
- Angle 90 degrees
- Average per chart 2.90
- Charts that have it 93.5%
- Of the five major ones 23.4%
- What it does rubs, and the rubbing builds
The square rubs, and the rubbing builds. What it links is what decides the subject, and that your chart answers. See yours free here.
