Free · Material quantities

Eight-Mode Area & Square-Meter Converter

Calculate area for rectangles, squares, circles, triangles and regular polygons, or convert a supplied area between units.

Calculator inputs

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Enter the known values in the units shown. Results update as you type.
Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
Use the worked example to check the method. Reset restores the starting fields.

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

A rectangle 2 m by 3 m has area 6 m². A triangle with sides 3 m, 4 m and 5 m also has area 6 m².

Rectangle A = length × width; circle A = πr²; triangle A = √[s(s − a)(s − b)(s − c)]

Enter these known values and leave the other values blank.

Polygon modes require regular pentagons, hexagons or octagons with equal sides and equal interior angles. An arbitrary polygon cannot be determined from one side length.
Triangle sides must be positive and satisfy all three strict triangle inequalities. Degenerate triangles are excluded.
Circle inputs use radius or diameter, with diameter equal to twice the radius. Custom mode converts an already known area.
Area alone does not include cutting waste, openings, overlap, substrate work or a structural design check.

Yes. Choose the unit for each input before typing its value; the geometry uses a common length basis.

The international acre is exactly 43560 square international feet; Bookify replaces the rounded captured area factor.