Square Footage Calculator
Calculate square footage for rectangles, triangles, circles, trapezoids and L-shapes. Results in sq ft, square metres, sq yards and acres.
๐ Runs entirely in your browser โ nothing is uploadedHow square footage is calculated
Square footage is a measure of surface area. For the most common case, a rectangular or square room, you multiply the length by the width, both in feet. A living room that is 15 feet long and 12 feet wide covers 180 square feet. Real spaces are rarely that simple, so this calculator handles five shapes: rectangles, triangles (half of base times height), circles (ฯ times the radius squared), trapezoids (the average of the two parallel sides times the height) and L-shapes, which are treated as two rectangles added together.
Any unit in, every unit out
You can measure in feet, inches, yards, metres or centimetres and the calculator converts automatically. The result is shown in square feet, square metres, square yards and acres, which covers real estate listings, flooring and carpet quotes, landscaping and land surveys. Square yards are the usual unit for carpet in the United States, while square metres are standard almost everywhere else. One square yard is exactly nine square feet, and one acre is 43,560 square feet.
Quantity and waste for real projects
If you have several identical areas, such as four equal garden beds or three matching rooms, enter the number in the quantity field instead of calculating each one. For materials that are cut to fit, such as flooring, tile, sod or paving, add a waste percentage; 5 to 10 % covers straight layouts and 10 to 15 % suits diagonal or patterned ones. The summary line spells out the arithmetic so you can double-check it or copy it into an estimate.
Measure the longest points of each section and round up to the nearest inch if you are ordering materials. For irregular rooms, break the plan into simple shapes, calculate each one with this tool and add the results. Everything runs locally in your browser, so your measurements stay private.
How to use
- Pick a shapeChoose rectangle, triangle, circle, trapezoid or L-shape and the unit you measured in.
- Enter the dimensionsType the lengths. The fields change to match the shape you selected.
- Add quantity or wasteOptionally multiply identical areas or add an overage percentage, then read the area in sq ft, mยฒ, sq yd and acres.