Area for 10 common shapes with formula and diagram.. Area Calculator is a free online tool from the ToolsRift Math Calculators collection. It runs entirely in your browser — nothing to install, no signup, and your data never leaves your device.
Pick a shape, type in its dimensions such as length, width or radius, and the area appears instantly along with the formula used.
Ten common shapes including square, rectangle, triangle, circle, parallelogram, trapezoid, rhombus, ellipse, sector and regular polygon — each with its own formula and inputs.
Area = π × r², where r is the radius. Enter the radius and the calculator multiplies it by pi automatically.
It is unit-agnostic — enter all measurements in the same unit (cm, m, in, ft) and the area is returned in that unit squared.