How Many Square Feet Is 20 × 21 ft?

"Square Footage Calculator" Calculator

How many square feet is 20 × 21 ft?

Answer

A rectangle of 20 × 21 ft covers

420 square feet

Any rectangle 20 ft wide and 21 ft long covers 420 square feet. The order of the sides makes no difference — 20 × 21 and 21 × 20 are the same area.

How the Square Footage Is Calculated

Square feet = width (ft) × length (ft)

Area is a product, not a sum: a rectangle holds as many one-foot squares as its width multiplied by its length. Put this rectangle into it:

20 ft × 21 ft

=

20 × 21

=

420 square feet

20 × 21 ft in Other Units

The same rectangle expressed the other common ways. The perimeter is the figure to use for skirting, edging or fencing — and it is what tells this rectangle apart from other sizes with the same area.

Square feet	420 square feet
Square meters	39.02 m²
Square yards	46.67 yd²
Perimeter	82 ft

Note: this is floor area. Wall area is height × length for each wall, and a room that is not a plain rectangle has to be split into rectangles first and added up.

Related Calculations

About "Square Footage Calculator" Calculator

This calculator works out the square footage of a rectangle from its two sides in feet. For example, it can help you find out how many square feet is 20 × 21 ft? (The answer is: 420 square feet). Enter the width (e.g. 20 ft) and the length (e.g. 21 ft) in feet — half-feet and decimals such as 10.5 are accepted.

"Square Footage Calculator" Calculator

Square Footage for a 20 ft Side

Size	Square Feet	Square Meters
6 × 20 ft	120 square feet	11.15 m²
7 × 20 ft	140 square feet	13.01 m²
8 × 20 ft	160 square feet	14.86 m²
9 × 20 ft	180 square feet	16.72 m²
10 × 20 ft	200 square feet	18.58 m²
11 × 20 ft	220 square feet	20.44 m²
12 × 20 ft	240 square feet	22.3 m²
13 × 20 ft	260 square feet	24.15 m²
14 × 20 ft	280 square feet	26.01 m²
15 × 20 ft	300 square feet	27.87 m²
16 × 20 ft	320 square feet	29.73 m²
17 × 20 ft	340 square feet	31.59 m²
18 × 20 ft	360 square feet	33.45 m²
19 × 20 ft	380 square feet	35.3 m²
20 × 20 ft	400 square feet	37.16 m²
20 × 21 ft	420 square feet	39.02 m²
20 × 22 ft	440 square feet	40.88 m²
20 × 23 ft	460 square feet	42.74 m²
20 × 24 ft	480 square feet	44.59 m²
20 × 25 ft	500 square feet	46.45 m²
20 × 26 ft	520 square feet	48.31 m²
20 × 27 ft	540 square feet	50.17 m²
20 × 28 ft	560 square feet	52.03 m²
20 × 29 ft	580 square feet	53.88 m²
20 × 30 ft	600 square feet	55.74 m²
20 × 31 ft	620 square feet	57.6 m²
20 × 32 ft	640 square feet	59.46 m²
20 × 33 ft	660 square feet	61.32 m²
20 × 34 ft	680 square feet	63.17 m²
20 × 35 ft	700 square feet	65.03 m²

Square Footage of a 20 × 21 ft Rectangle

"Square Footage Calculator" Calculator