How Many Square Feet Is a 20x20 Room?
Total area
400 sq ft
Twenty feet by twenty feet.
How that number is worked out
These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.
- Length20 ft
- Width20 ft
- How many rooms or areas this size1
- Extra area to add0 sq ft
Total area400 sq ft
| One area | 400 sq ft |
|---|---|
| Times 1, plus extra | 400 sq ft |
| Square yards | 44.44 |
| Square meters | 37.16 |
| Perimeter of one area | 80 ft |
What else matters here
Four hundred square feet is the standard two car garage that everybody says is too small, a large great room, or a studio apartment in most cities. It is four roofing squares, four hundred square feet of slab, and the point at which every material category needs a joint, a seam or a break somewhere.
A 20 foot span is also structurally significant. A clear span of that length in a floor or ceiling needs engineered joists or a beam, whereas anything up to about 16 feet can usually be done with dimensional lumber. That is why so many rooms stop just short of 20 feet.
What this calculator assumes
- Length times width, times how many areas are that size. For an L shaped room, split it into two rectangles and run this twice.
- Square yards are square feet divided by nine, which is how carpet is still quoted in much of the country.
Questions people ask
How many square feet is a 20x20 room?
400 square feet, which is 44.44 square yards and 37.16 square meters.
Is 20x20 big enough for a two car garage?
It is the common minimum and it is tight. Two mid size cars fit, but opening both doors fully and walking around them does not. 24 by 24 is the size most people wish they had built.
How much concrete for a 20x20 slab?
About 5.4 cubic yards at four inches with waste, or 8.1 at six inches. There is a page for that exact slab on this site.
The square footage calculator takes any dimensions you like and hands back the same list.