Square Footage Calculator

Add one or more areas, type your measurements and get the total in square feet, square yards, square meters and acres.

How to calculate square footage

Square footage is the area of a surface measured in square feet. Measure in feet, then use the formula for the shape:

Shape	Formula	Example
Rectangle or square	length × width	12 × 10 = 120 sq ft
Triangle	½ × base × height	½ × 6 × 4 = 12 sq ft
Circle	π × (diameter ÷ 2)²	π × 5² = 78.54 sq ft for a 10 ft circle

How to measure a room with an irregular shape

Break an L-shaped room, an alcove or a bay into simple shapes. Measure each one, calculate its area and add them up. In this calculator that means one area per piece: press “Add another area” for each extra piece and the total updates as you type.

Feet, inches, yards and meters

Most tape measures show feet and inches. You can type a measurement exactly as you read it, for example 10'6" or 10 ft 6 in, and the calculator turns it into feet. To measure in another unit, pick it from the menu next to the number.

Unit	Equals
1 square foot	144 square inches
1 square yard	9 square feet
1 square foot	0.09290304 square meters
1 acre	43,560 square feet

The square meter figure follows from the international foot, which is defined as exactly 0.3048 meters. Squared, that gives 0.09290304 square meters per square foot.

Example: a living room with a bay window

A living room measures 18 ft by 14 ft, and the bay window alcove adds a rectangle of 6 ft by 4 ft. You plan to add 10% waste for cutting.

Step	Operation	Result
Main room	18 × 14	252 sq ft
Bay alcove	6 × 4	24 sq ft
Total	252 + 24	276 sq ft
With 10% waste	276 × 1.10	303.6 sq ft

Square feet of common room sizes

Room size	Square feet	Square yards
8 ft × 8 ft	64	7.11
10 ft × 10 ft	100	11.11
12 ft × 12 ft	144	16
12 ft × 16 ft	192	21.33
20 ft × 20 ft	400	44.44

Frequently asked questions

How do I calculate square footage?

For a rectangle, multiply length by width, both in feet. A room that measures 14 ft by 12 ft is 14 × 12 = 168 square feet. For an odd shape, split it into rectangles, calculate each one and add the results.

How many square feet is a 12x12 room?

144 square feet, because 12 × 12 = 144. That is also 16 square yards.

How many square feet is 8x8?

64 square feet, because 8 × 8 = 64.

What is the square footage of a 20x20 room?

400 square feet, because 20 × 20 = 400.

How do I calculate square feet from inches?

Divide each measurement by 12 to get feet, then multiply. Or multiply the inches first and divide the result by 144, since one square foot is 12 × 12 = 144 square inches. A 60 in by 48 in panel is 60 × 48 ÷ 144 = 20 square feet.

How do I measure feet and inches?

Type them the way you read them off the tape, such as 10'6" or 10 ft 6 in. The calculator converts the inches for you. You can also pick inches, yards or meters from the unit menu next to each measurement.

How much extra should I add for waste?

It depends on the material and the pattern, so follow the installation guide of the product you are buying. Enter that percentage in the waste box and the calculator adds it to the total.