Calculate room or surface area, include waste, convert between units, and estimate project cost for US and UK spaces.
This square footage calculator is for planning and estimating only. Always verify your own measurements, deduct openings where needed, and check manufacturer coverage rates before ordering materials.
freeusukcalculator.com
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For a rectangular space, square footage is simply length Γ width in feet. A room 12 ft by 10 ft is 120 square feet. For irregular spaces, the reliable method is to divide the area into simple rectangles and triangles, calculate each piece, and add them together. A triangle's area is Β½ Γ base Γ height, and a circle's is Ο Γ radiusΒ².
If your measurements are in inches, divide by 12 before multiplying, or measure in feet with decimals (for example 10 ft 6 in = 10.5 ft). To convert the result, multiply square feet by 0.0929 to get square metres.
Square footage drives how much material you buy for flooring, tiling, painting, carpeting or turf. Because material is priced by area, an accurate measurement prevents both costly over-ordering and the bigger headache of running short mid-project.
Always add a waste allowance: about 10% for straightforward rectangular rooms and up to 15β20% for diagonal layouts, patterned tile or rooms with many cuts around fixtures. For paint, remember coverage is quoted per coat β most walls need two β so double the area when estimating tins. Measuring each room separately and labelling your figures keeps a multi-room project organised.
Multiply length by width in feet for a rectangular space (length ft Γ width ft = square feet). For odd shapes, split the area into rectangles and triangles, calculate each, and add them together.
Use area = Ο Γ radiusΒ². For a circle 10 feet across, the radius is 5 feet, so the area is 3.1416 Γ 25 β 78.5 square feet. The calculator supports circular areas too.
Multiply square feet by 0.0929 to get square metres, or multiply square metres by 10.764 to get square feet. The calculator switches units automatically.
Material is priced and sold by area. Knowing the square footage lets you buy the right amount of flooring, tile or paint β add about 10% extra for cuts, waste and second coats.