Square Footage Calculator
Measure a room, house, garden or plot by adding up its rectangular, circular and triangular parts — and see the total in square feet, square metres and square yards, plus an optional cost.
180 sq ft
Rectangle = length × width; circle = π × (diameter ÷ 2)²; triangle = ½ × base × height. For L-shaped or irregular rooms, split the floor into rectangles and add each as a separate area. No waste allowance is included — flooring and tile usually need 5–15% extra for cuts.
180
Square feet
16.72
Square metres
20
Square yards
Add a price
Estimated cost
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How to use square footage calculator
- 1Choose the unit you measured in — feet, inches, yards, metres or centimetres.
- 2Enter the dimensions of each area; add more areas for L-shaped or irregular spaces.
- 3Optionally add a price per square foot or square metre.
- 4Read the total area and estimated cost.
About this tool
Square footage is length × width for rectangles, π × (diameter ÷ 2)² for circles and ½ × base × height for triangles. A 12 × 15 ft room is 180 sq ft (16.7 m²). For an L-shaped room, measure it as two rectangles and add them; for a room with a bay, add the rectangle and a triangle or half-circle.
Results are given in square feet, square metres and square yards, using exact conversions (1 ft = 0.3048 m), so you can mix measurements from US and metric sources. Adding a price per unit area gives a quick estimate for flooring, turf, carpet or painting quotes.
No waste allowance is added. When buying flooring, tile or carpet, add 5–10% for cuts and offcuts — more for diagonal patterns or rooms with many corners.
Frequently asked questions
Measure the length and width in feet and multiply them. A 10 × 12 ft room is 120 square feet. For irregular rooms, split them into rectangles and add the areas together.
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