Which shapes are supported?

Circle, square, rectangle, and triangle (base × height / 2). Enter the required dimensions for each.

Use any consistent unit (e.g. cm). Area and perimeter are in the same unit² and unit respectively.

For a generic triangle you need three sides; this tool uses base and height for area only (no perimeter for triangle).

Online Geometric Shapes Area and Perimeter Calculator

Pick a shape and enter dimensions to get area and perimeter. Circle, square, rectangle, triangle.

Shape

Radius

Which shapes are supported?: Circle, square, rectangle, and triangle (base × height / 2). Enter the required dimensions for each.
Units?: Use any consistent unit (e.g. cm). Area and perimeter are in the same unit² and unit respectively.
Triangle perimeter?: For a generic triangle you need three sides; this tool uses base and height for area only (no perimeter for triangle).

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Convert Celsius to Fahrenheit and Fahrenheit to Celsius instantly. Free temperature converter.

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Calculate C(n,r) — the number of ways to choose r items from n without order. Uses n!/(r!(n-r)!).

Combinations with Replacement Calculator

Calculate the number of ways to choose r items from n with repetition allowed. Formula: C(n+r-1, r).

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Count how many permutations of n objects are even (expressible as an even number of swaps). For n ≥ 2, equals n!/2.