Home & construction
Square Footage Calculator
Enter the length and width to get the area in square feet, square yards and square metres.
The formula
square feet = length × width × areas
square yards = square feet ÷ 9
perimeter = (length + width) × 2 × areas
Worked example
A 20 ft × 14 ft living room
- 20 × 14 = 280 ft²
- 280 ÷ 9 = 31.11 yd²
- (20 + 14) × 2 = 68 ft of perimeter
Where this goes wrong
Dividing square feet by three to get square yards
A square yard is three feet by three feet, so it holds nine square feet, not three. Divide 280 ft² by 3 and you order 93 yd² instead of 31 — three times too much carpet. Areas scale with the square of the length factor, every time.
Questions
- How do I measure a room that is not a rectangle?
- Split it into rectangles, work out each one, and add them together. An L-shaped room is two rectangles; a bay window is a rectangle plus a shallow one. Measuring the longest points and multiplying overstates the area every time.
- Should I measure to the wall or to the baseboard?
- To the wall, then take off nothing. Flooring runs under the baseboard in most installations, and the waste allowance you add later covers the difference either way.
- How much waste should I add?
- That depends on the material and the layout, not on the area — so it is not applied here. The tile and flooring calculators add it, because there the offcuts are what force you into another box.