Square Footage Calculator

Square footage is the floor area of a space. It is the starting point for ordering flooring, carpet, underlay, insulation, sod or paint primer, and it is how many trades price their work.

Rooms are rarely perfect rectangles, so the calculator lets you add several areas and totals them. An L-shaped living room becomes two rectangles; an open-plan floor becomes the kitchen, dining and living zones added together. Each area shows its own result so you can price rooms separately.

1. Measure the length and width of the first rectangle, wall to wall.
2. Enter the measurements. In US mode the default is ft + in, so 10 ft 6 in can be typed exactly as measured. Choose metres, centimetres or millimetres from the unit menu if you prefer.
3. Select “Add another area” for each additional rectangle and give it a name if helpful.
4. Optionally enter a price per square foot or square metre to estimate cost.

Area = Length × Width

Total area = Area₁ + Area₂ + … + Areaₙ

Both measurements must be in the same unit. Convert inches to feet by dividing by 12 (6 in = 0.5 ft). To convert the result, 1 square foot = 0.0929 m², 1 m² = 10.764 sq ft and 1 square yard = 9 sq ft.

For a triangular area, use half of base × height. For a circle, use π × radius². You can enter these as an equivalent rectangle, for example a triangle with a 10 ft base and 8 ft height as 10 ft × 4 ft.

An L-shaped room is split into two rectangles:

• Main section: 12 ft × 10 ft 6 in = 12 × 10.5 = 126 sq ft
• Alcove: 8 ft × 5 ft = 40 sq ft
• Total: 166 sq ft (15.42 m², or 18.44 sq yd)

In metric, a 4.2 m × 3.5 m bedroom is 14.7 m² (158.2 sq ft). If flooring costs 32 per m² installed, the estimate is 14.7 × 32 = 470.40 before waste.

• Total area – the sum of every area in your preferred unit.
• Square metres / square feet / square yards – the same total in other units. Carpet is often priced per square yard in the US.
• Area by room – each rectangle on its own.
• Estimated cost – total area × your price, with no waste allowance.

• Measure at floor level, wall to wall, and ignore skirting boards and baseboards.
• Measure each wall: rooms are often slightly out of square, so use the longer measurement.
• Include closets and alcoves if they will receive the same flooring.
• Sketch the floor plan first and label each rectangle before measuring.

Area is not the same as the quantity to buy. Flooring needs a waste allowance for cuts and pattern matching: typically 5–10% for a straight lay and more for diagonal or herringbone patterns. Sheet goods and rolls are sold in fixed widths, which can add more.

To turn your area into materials, use the tile calculator for tiles and boxes or the paint calculator for walls. For anything with depth, such as gravel or soil, use the cubic yard calculator.

Note that real estate listings use specific measurement standards for “living area” that may exclude garages, unfinished spaces or low-ceiling areas. This calculator measures plain floor area.