Square Footage Calculator
Add up the area of rooms and spaces of any shape in square feet, square meters and square yards, with waste and cost.
Results
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Square feet
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Square meters
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Square yards
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Acres
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Areas
| Area | Shape | Measurements | ft² | m² |
|---|
How it's worked out
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How to use the square footage calculator
- Choose the shape of the first area and the unit you measured in (feet, inches, yards, meters, centimeters or millimeters).
- Enter the measurements. The boxes change to match the shape, for example length and width for a rectangle.
- Press "Add another area" for each extra room or section, such as a closet or a bay window. Each area can use its own unit.
- Add a waste allowance if you are buying flooring, tile or turf, and a price to see the cost.
Area formulas
- Rectangle or square: length × width.
- L-shape: overall length × overall width − cut-out length × cut-out width.
- Triangle: base × height ÷ 2 (height measured at a right angle to the base).
- Circle: π × (diameter ÷ 2)², where π ≈ 3.14159.
- Half circle: half the area of the full circle.
- Trapezoid: (side 1 + side 2) ÷ 2 × height, where sides 1 and 2 are the two parallel sides.
Each area is worked out in the unit you entered, converted to square meters, and added to the others. The total is then shown in square feet (× 10.764), square yards (× 1.196) and acres. The waste allowance multiplies the total by (1 + waste ÷ 100).
Worked example: an L-shaped living room
A room measures 20 × 15 ft overall, but an 8 × 5 ft corner belongs to the hallway.
- Full rectangle: 20 × 15 = 300 ft².
- Cut-out corner: 8 × 5 = 40 ft².
- Room area: 300 − 40 = 260 ft², which is 260 × 0.0929 = 24.15 m².
- Laminate with 10% waste: 260 × 1.10 = 286 ft² to buy.
- At $2.50 per ft², that costs 286 × $2.50 = $715.
How to measure a room accurately
- Measure along the floor from wall to wall, not along the baseboard tops, and write each figure down straight away.
- Round up to the nearest inch or centimeter. Buying slightly too much is cheaper than a second trip.
- For an irregular room, sketch it and split it into rectangles and triangles, then add each one as its own area.
- Include closets and alcoves if the flooring or carpet will run into them; leave out areas under fitted cabinets.
- Convert feet and inches to decimal feet before entering them: divide the inches by 12, so 10 ft 9 in is 10.75 ft.
Area conversions
| Unit | Square feet | Square meters |
|---|---|---|
| 1 square inch | 0.00694 | 0.000645 |
| 1 square foot | 1 | 0.0929 |
| 1 square yard | 9 | 0.8361 |
| 1 square meter | 10.764 | 1 |
| 1 acre | 43,560 | 4,046.86 |
| 1 hectare | 107,639 | 10,000 |
Frequently asked questions
How do I calculate the square footage of a room?
Measure the length and width of the room in feet and multiply them. A room 12 feet by 15 feet is 12 × 15 = 180 square feet. If you measure in feet and inches, turn the inches into a decimal first: 12 feet 6 inches is 12.5 feet.
How do I measure an L-shaped room?
Either split it into two rectangles and add them, or measure the full rectangle around it and subtract the missing corner. Choose the L-shape option, enter the overall length and width, then the length and width of the cut-out corner.
How do I convert square feet to square meters?
Multiply square feet by 0.0929, or divide by 10.764. 180 square feet is 180 × 0.0929 = 16.72 square meters. To go the other way, multiply square meters by 10.764.
How much extra flooring should I buy?
Flooring suppliers usually recommend about 10% extra for cuts and waste in a straight layout, and around 15% for diagonal or herringbone patterns or rooms with many corners. Enter the percentage in "Extra for waste" to include it.
Why doesn’t my total match the square footage on my house listing?
Listings and appraisals measure a home’s finished area from the outside of the exterior walls, so they include wall thickness, hallways and closets. Adding up the rooms measured inside will always give a smaller number.