Why? How?
I would imagine it’s for ease of storage.
Because making square boxes is a lot easier than a closer polygon; they’re also easier to open and close and more forgiving to variations in the shape of the pizza itself. There would be no savings in amount of cardboard (which anyway is cheap), it doesn’t store or travel better… so why would anybody do anything more complicated for no benefit? (cue jokes about consulting firms).
A square box stores flat and can be folded into shape in seconds. My local pizzeria puts the pizza onto the unfolded box, slices if, then folds the box around it. I can’t imagine a round box that would be nearly as easy to store and use.
It’s obviously much easier to make a rigid square box out of a flat piece of cardboard.
I guess you could ask why a pizza isn’t square. Aside from tradition, why would a pizza maker want to fill up the box? Better to make a smaller quantity of product appear larger with an ill-fitting box.
As a pizza expands and contracts during baking, surely something round keeps its shape better. Was this not why many things made of iron were cast round and curvy rather than square and straight?
Round pizza base is easier to construct than square. You just twirl it round and fling it in the air, in that way they do in the good pizza places. Centrifugal force does the work for you. Trying to make a square shape you have to push it out on the pan … I guess you could do a rolling pin technique, but that would probably take longer and would be bad for the fluffiness of the base.
Surely the box is not traditional? But many types of bread are round, dating back to ancient times and even before, so one should not wonder at a round, hand-tossed pizza. I certainly have seen the occasional rectangular pizza and tarte flambée, though, and even an octagonal pizza box.
ETA in short the pizze aren’t always round nor the boxes invariably square.
Even if you don’t do the twirling in the air technique (which I believe many pizza restaurants do not), you still get a mostly circular crust by taking a roughly spherical blob of dough and flattening it out with a rolling pin. Put it in a round pan and trim off any overflow and it’s round. There’s a bit more involved, but that’s the essence.
They could make square or rectangular pizza and some do, but as said above, it takes more work than a round one.
Baking trays are usually rectangular. The issue with older techniques and metal implements was the weak joints.
Follow the money!
Why? Because round (or hexagonal or octagonal) boxes are way more expensive than square/rectangular ones. Square ones are a standard item for cardboard box companies; other shapes would be a custom design, requiring changes to the manufacturing/cutting process.
And given how price-sensitive the pizza industry is, most customers would never pay more to have it come in a round box. Isn’t like that would make it taste better!
Because it’s part of a pot sobriety test, as related to me by a friend:
“Why is the box a square, when the pizza is a circle and all the pieces are triangles?”
Most pizza places around here make square pizzas if they’re twelve cut or larger. These are usually thicker, too.
But the square boxes for round pizza do exactly what they need to do. A round box is no betterr.
Pie are round. Cake are square.
Some places make polygonal or round containers or the pizza. Domino’s box has cut-off corners. I’ve had octagonal boxes. One place in Salt Lake City sent their pizzas out in circular styrofoam containers.
But, as noted above, square boxes are easier to make, store, and fold.
“You better cut the pizza into four pieces because I’m not hungry enough to eat six.” ~Yogi Berra
I know a guy whose house is a geodesic dome. One selling point is that they use less require materials to build, a sphere being more efficient than a cube. However, he says, getting them worked on is murder. Making things square and plumb is one thing…but faceted is another, I guess. Imagine cutting and installing shingles, for instance, on this place:
https://images.app.goo.gl/ZtAKMFwCmgbfc6Er8
The labor, sheesh. Anyway…square boxes will be much easier to create.
I was working at Domino’s in the 80s when they adopted the box with the cut off corners. They took about twice as long to put together than the square boxes. That labor to cardboard cost ratio only works if you have drivers waiting around with nothing more productive to do than fold boxes.
I saw what you did there.
Ease of getting your piece of pizza out to eat.
A square box with a round pizza gives you the open corners to grab your piece. A round box that is close to the diameter of the pizza (to save costs) would leave little room between the box sides and the pizza to slide your fingers under the pizza slice.
In St. Louis pizza is baked round and cut into squares! But it still comes in a square box.
Imo’s Pizza, the square beyond compare!