Calculate the area of a rectangle, square, triangle, circle, ellipse or trapezoid, and the surface area of a sphere or closed cylinder. Enter measurements in metres; results are in square metres.
Rectangle = length × width. Triangle = base × perpendicular height / 2. Circle = πr². Ellipse = πab. Trapezoid = (a+b)h/2. Sphere = 4πr². Closed cylinder = 2πr(r+h).
A 4 m by 3 m room has an area of 12 m². A circle with radius 3 m has an area of 9π ≈ 28.274334 m². Its diameter is 6 m.
Gross area = sum of each length × width. Net area = gross area − exclusions. Material area = net area × (1 + allowance / 100).
A room made of 4 × 3 m and 2 × 1.5 m rectangles totals 15 m². After subtracting 1 m², the net area is 14 m². A 10% allowance gives 15.4 m² of material.
Do not overlap rectangles when splitting an L-shaped floor. Material allowance is not an industry recommendation: cuts, board direction, packaging and breakage can change the quantity you must buy. The calculator does not round up to whole packs.
Radius is half the diameter. An ellipse uses semi-axes, not full widths. Cylinder surface area includes both circular ends; it is not cylinder volume. Convert every dimension into metres before entering it. Irregular spaces need to be split into measurable shapes.
Divide the floor into non-overlapping rectangles, measure each in the same unit, then use the combined-area form. Alternatively, subtract the missing rectangle from a larger surrounding rectangle. Both methods should agree.
One square metre is approximately 10.7639104 square feet. Square the length conversion factor because area has two dimensions. A 12 m² room is about 129.17 ft².
References support the identified formula, unit or jurisdiction. They do not imply endorsement of this site. Check the original document for current conditions and exceptions.
English edition: 16 September 2026.