The right angle and its seven degrees
A square is a quarter of the circle. The orb used here is seven, so eighty three to ninety seven degrees of separation qualifies. Pluto is effectively fixed on a human timescale, so the Sun makes the aspect alone, crossing each fourteen degree band in about a fortnight.
Two squares form each year, giving something like seven or eight per cent of births. The sign pair is generational, since Pluto stays in a sign for between roughly twelve and thirty years, and Pluto is retrograde for close to half of each year, which makes a natal retrograde Pluto entirely unremarkable. The uneven sign lengths come from the elliptical orbit rather than from anything the tradition assigns meaning to.
Friction with no line of sight
The Sun is conscious purpose. Pluto is compulsion, buried power, the part of a chart that does not bargain. In an opposition they face each other and the tension is at least visible. In a square they sit at an angle where neither is in view of the other, which is why the tradition reads squares as pressure that has to be discharged rather than resolved.
The usual descriptions involve control, resistance to being controlled, and a tendency to rebuild the same situation repeatedly until something changes. Also credited to the aspect is unusual persistence, on the reasoning that the friction never lets the subject settle for a version that does not work.
None of that is a verdict, and the language attached to Pluto aspects is heavier than the aspect deserves in most charts. A square describes where a chart does work, not what happens to a person. It is also worth remembering that a fortnight of births carries it twice a year, so any description that fits everyone who has it is necessarily describing something very general.
Mode, house and the individual layer
Squares generally join signs of the same mode. Cardinal versions read as repeated confrontation and fresh starts. Fixed versions as long entrenchment followed by a hard break. Mutable versions as a theme that keeps changing shape without going away. The exception is a square that crosses a sign boundary at a wide orb, where the two signs no longer share a mode and the neat description stops applying.
The houses are the personal part. A square between the tenth and the first points the pressure at public role and self-presentation. Between the fourth and the seventh it points at family and partnership. Those readings are unrelated to each other, and only a birth time can tell you which one applies, since the houses turn a degree every four minutes. That single piece of data does more work here than everything else on this page.
How much weight to give it
Inside two degrees this is a genuine structural feature and most people recognise the description straight away. Between two and four it is one theme among several. Beyond five it is thin, and a seven degree Sun square Pluto in a chart where nothing else contacts Pluto is background rather than the story.
What raises it is repetition: an angle involved, the Moon on the same degrees, or a second contact to Pluto from a personal body. Without any of that, a generational aspect stays generational, and the useful reading is the one that says so instead of promising an intense destiny.
The check above reports the exact orb, so you can weigh this from a measurement rather than from a keyword.
Questions people ask about this
Is Sun square Pluto a bad aspect?
The tradition does not treat squares as bad, only as friction that has to go somewhere. This one is read as pressure between conscious direction and something that will not concede, and the outcome depends on placement and on the rest of the chart.
How common is Sun square Pluto?
Around seven or eight per cent of births. Two squares form each year, one on each side of Pluto, and the Sun spends about a fortnight inside the seven degree orb each time.
Why do descriptions of this aspect sound so heavy?
Pluto attracts dramatic language, and squares attract more of it. In most charts the aspect is one feature among many. It deserves weight when the orb is tight or when a personal point is involved, and much less otherwise.
What does the square do that the conjunction does not?
A conjunction fuses the two so they are experienced as one thing. A square keeps them separate at an angle where neither is visible to the other, which is why it is described as recurring pressure rather than a permanent trait.
Does a retrograde Pluto make it stronger?
No. Pluto is retrograde for close to half of every year, so about half of all charts have it. It is the ordinary case and is not read as an intensifier.
What is the first thing to check?
The orb, then the houses. A tight square in an active pair of houses is worth reading carefully. A wide one with no supporting contacts is background, and treating it as more than that distorts the whole chart.