Window and Door Calculators
Windows and doors are sold by a size that is not a measurement, quoted by a number that is not a price, and searched for almost entirely by cost.
The calculators
The size on the sticker is a call size. A window described as 3050 is nominally 3 ft 0 in by 5 ft 0 in and is none of those dimensions exactly. Unit size, rough opening and call size are three different numbers, and every trade uses a different one, which is why a window ordered by the number on the old one arrives wrong often enough to be a running joke.
Measure the actual opening, in three places each way, and order to the unit size the manufacturer publishes.
What a window quote actually contains
Almost none of it is the window. On a replacement job the unit is typically a minority of the invoice: the rest is removal, disposal, flashing, interior trim, exterior capping and labour. Which is why a quote per window is nearly meaningless for comparison unless both quotes cover the same scope, and why the cheapest quote is frequently the one doing the least.
The single biggest scope difference is insert against full-frame. An insert leaves the old frame in the wall. A full-frame replacement takes it out and rebuilds the opening. They are different jobs with the same name, and the second one is the reason a quote can be double.
Why this section is nearly all cost searches
Because there is very little to calculate. A window is a manufactured unit, and unlike a deck or a slab there is no takeoff to do: you count them. So the questions people actually have are about money, and the pages here carry published prices with a byline and a date, quoted as that publisher's figures rather than ours.
The one thing there IS to calculate is whether the window is legal in the room it is going in, and that is a measurement almost nobody takes correctly.
Doors have the same problem in a different unit
R311.2 wants 32 inches of clear width on the egress door, measured between the face of the door and the stop with the door open 90 degrees. That is not the width printed on the door, and a 32 inch door does not give 32 inches of clear width.