Square feet calculator
Enter the length and width of up to six rooms, or the sides of another shape, in the unit you measured. The page adds them up in square feet, square metres, square yards and acres, and works out the cost if you enter a price.
- Rooms and shapes
- Free, no sign-up
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How to use it
- Pick the shape: rooms, circle, triangle, trapezoid or L-shape.
- Choose your unit and enter the measurements.
- Read the area in each unit, and the cost if you entered a price per square foot.
Formulas used
A rectangle is length × width, a circle is π × radius², a triangle is half of base × height, and a trapezoid is the average of the two parallel sides × the height. An L-shaped room is split into two rectangles and added. Measurements in inches, yards, metres or centimetres are converted first.
For flooring and tiles, add 5 to 10% for cuts and waste. One square metre is 10.764 square feet, a square yard (gaj) is 9 square feet and an acre is 43,560 square feet.
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Questions
How do I calculate square feet?
Multiply the length by the width in feet. A room 12 ft by 10 ft is 120 square feet.
How many square feet is a 4 m by 3 m room?
12 square metres, which is about 129.2 square feet. Choose metres as the unit and the page converts it.
How do I measure an L-shaped room?
Split it into two rectangles, measure each, and use the L-shaped room option, or enter them as two rooms.
How much flooring should I buy?
Buy the area plus 5 to 10% for cuts and waste, more for diagonal patterns.