Rectangle formulas
Area = width * height. Perimeter = 2 * (width + height). Diagonal = sqrt(width^2 + height^2) using the Pythagorean theorem.
A = w * h, P = 2(w + h), d = sqrt(w^2 + h^2)
The three main rectangle measurements.
Rectangle Calculator
Calculate area, perimeter, and diagonal of a rectangle from width and height.
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Result
Area
15
Perimeter
16
Diagonal
5.83
P = 2(5 + 3) = 16
d = √(5² + 3²) = 5.83
Also in General
Geometry
Rectangle area, perimeter, and diagonal
The rectangle calculator computes the area, perimeter, and diagonal of a rectangle from its width and height.
Limitations
This calculator assumes a standard rectangle with right angles. For parallelograms or other quadrilaterals, use a dedicated tool.
Frequently asked questions
The straight line from one corner to the opposite corner. It divides the rectangle into two right triangles.
Yes. A square is a special rectangle where all four sides are equal.
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