How to Calculate Square Footage

How do you calculate the square footage of a room?

Multiply the room's length by its width, both measured in feet. The result is the area in square feet (sq ft or ft²), which is the number of 1 foot by 1 foot squares that would cover the floor.

Measure wall to wall at floor level along the longest straight runs, and round to the nearest inch. For a bedroom that measures 12 feet by 14 feet, the area is 12 × 14 = 168 sq ft. The square footage calculator does the same multiplication and also gives the result in square meters (15.61 m²), square yards (18.67 yd²) and acres.

How do you find square feet when measurements are in feet and inches?

Convert the inches to a decimal fraction of a foot first by dividing them by 12, then multiply. A room that measures 12 feet 6 inches by 10 feet 3 inches becomes 12.5 ft × 10.25 ft = 128.13 sq ft.

Alternatively, convert everything to inches, multiply, and divide by 144, since one square foot is 12 × 12 = 144 square inches. The same room is 150 in × 123 in = 18,450 sq in, and 18,450 ÷ 144 = 128.13 sq ft. Either way gives the same answer.

How do you calculate square footage of an L-shaped or irregular room?

Divide the floor into rectangles that do not overlap, find the area of each, and add them together. Sketch the room on paper first and write each measurement on the sketch so nothing is counted twice.

Say a living room has a 12 × 14 ft main area plus a 6 × 8 ft dining nook. The main area is 168 sq ft, the nook is 48 sq ft, and the total is 168 + 48 = 216 sq ft. If a space has a notch cut out, such as a closet that juts into the room, you can also measure the full rectangle and subtract the missing piece.

How do you calculate square footage of circles and triangles?

Use the area formula for the shape, with all measurements in feet. The area calculator handles these and other shapes, and the square footage calculator includes circle, triangle, trapezoid and border tools.

How do you calculate the square footage of a house?

Add up the square footage of every finished, heated living space. You can measure room by room and add the results, or, for a quicker estimate, measure the outside of the house and multiply length by width for each rectangular section, then add each floor.

The two methods give different numbers. Measuring the exterior includes the thickness of the walls, so it comes out larger than the sum of interior room measurements. A 40 × 50 ft single-story house measured outside is 2,000 sq ft. Garages, unfinished basements, open porches and attics usually are not counted as living area. In the United States, appraisers commonly follow the ANSI Z765 standard, which measures finished, above-grade space from the exterior walls and reports below-grade areas separately. The square footage in a listing may follow a different method, so if the number matters for a price, ask how it was measured.

How many square feet are in an acre?

One acre is exactly 43,560 square feet. That equals about 4,046.86 square meters, 4,840 square yards or 0.4047 hectares. An acre does not have to be square: a strip 66 ft wide and 660 ft long (one chain by one furlong, the historical definition) is also exactly 43,560 sq ft. A square acre is about 208.71 ft on each side.

To convert square feet to acres, divide by 43,560. A 100 × 150 ft lot is 15,000 sq ft, or 15,000 ÷ 43,560 = 0.3444 acres. To go the other way, multiply acres by 43,560. The acreage calculator converts lot dimensions to acres, hectares and square feet, and also handles four-sided lots that are not rectangles.

How do you convert square meters to square feet?

Multiply square meters by 10.7639 to get square feet, or divide square feet by 10.7639 to get square meters. The factor comes from 1 foot = 0.3048 meters exactly, so 1 sq ft = 0.09290304 m². A 4 × 5 meter room is 20 m², which is 215.28 sq ft.

To convert square feet to square yards, divide by 9, since a yard is 3 feet and 3 × 3 = 9. The 168 sq ft bedroom is 18.67 square yards, the unit carpet is sometimes priced in.

How much flooring, paint or material do I need?

Start with the measured square footage, then add a margin for cutting and waste before you buy. Many installers add about 5% to 10% for straight-laid flooring and more for diagonal patterns or rooms with many corners; the product's instructions or your installer can give a specific figure.

The square footage calculator also estimates cost when you enter a price per square foot. At $4.00 per sq ft, flooring for the 168 sq ft bedroom costs $672.00 before waste and installation. For landscaping jobs measured in area and depth, such as mulch, see how much mulch do I need.