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Square Footage Calculator
Work out the area of any room by adding up rectangles, triangles, circles, and trapezoids, and taking away what is not floor, in square feet and square metres at once.
Square Footage Calculator: Each shape's area is worked out with its usual formula, including Heron's formula for a triangle from its three sides, and the shapes are added or taken away. The total is shown in square feet, square metres, and square yards; one square metre is 10.764 square feet. Runs 100% locally in your browser with zero server file uploads.
- Category
- Home & family tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
Split an L-shaped or irregular room into rectangles and other shapes, add them up, and tick Subtract for parts that are not floor, such as a chimney breast or a built-in cupboard. For flooring, add 5 to 10% for cutting waste.
A worked example
An L-shaped room made of a 12 × 15 ft rectangle and a 6 × 8 ft one has 180 + 48 = 228 ft², which is 21.18 m². With 10% extra for waste, buy flooring for about 251 ft².
For the walls of the same room, the wallpaper calculator counts rolls.
Units
A foot is exactly 0.3048 m, so a square foot is 0.09290304 m² and a square metre 10.764 ft². A square yard is 9 ft², or 0.836 m², the unit carpet is often sold in.
How to use it
- Choose the unit you measured in.
- Add a shape for each part of the room and enter its measurements; tick Subtract for parts to leave out.
- Read the total in square feet, square metres, and square yards.
Privacy & limitations
Everything is worked out in your browser.
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Frequently asked questions
How do I measure an L-shaped room?
Split it into two rectangles that do not overlap, measure each, and add them. Or measure the whole bounding rectangle and subtract the missing corner.
How much extra flooring should I buy?
Usually 5 to 10% more for cutting waste, and more for diagonal layouts or patterned tiles.
How do I measure a bay window?
Treat it as a trapezoid: the two parallel sides are the opening in the wall and the front of the bay, and the height is how far the bay sticks out.
Free tool · runs in your browser · no account required