Square Footage Calculator

Multiply length by width when both are in feet. A room 12 feet by 10 feet is 120 square feet. If a measurement is in inches, divide it by 12 to get feet first. For a whole house or an odd layout, split it into rectangles, find each area, and add them up. This square footage calculator does that for you, so you'll add several rooms at once.

Break the floor plan into rectangles, one per room or section, work out each as length times width, and add the results. A 12 by 10 bedroom (120 sq ft) plus a 15 by 14 living room (210 sq ft) is 330 square feet together. Use the add-room button above to total as many spaces as you'll need. Closets and hallways count too, so don't skip them.

A 10 by 10 room is 100 square feet, since 10 times 10 is 100. A 12 by 12 room is 144 square feet, and a 10 by 12 is 120. Those round numbers make 10x10 a common reference, and that's roughly the size of a small bedroom or office. Enter your own dimensions above for any room size.

Multiply square feet by 0.0929 for square meters, or divide by 43,560 for acres. So 1,000 square feet is about 92.9 square meters, and an acre is 43,560 square feet. The result above shows all three at once, which you'll want for metric plans or for land where acres are the usual unit.

Take the total square footage, add 10% for cuts and waste, then divide by the coverage of one box or roll. If a box covers 20 square feet and you need 220 with waste, that's 11 boxes. Patterned or diagonal layouts want a bit more, closer to 15%. The flooring estimate above does this once you enter the box coverage.

Split it into rectangles. Draw a line to divide the L into two rectangles, measure each as length by width, and add the two areas. The same trick works for any odd shape: break it into rectangles, triangles, or a circle, total them, and you've got the full square footage. The add-room feature above makes it easy, so you won't fuss with the geometry.