## About This Tool

The online Rectangle Calculator is used to calculate the area, perimeter and diagonal of a rectangle.

## Rectangle

In geometry, a rectangle is any quadrilateral with all four interior angles 90° (right angles).

## Formulas

The following is the calculation formulas of the area, perimeter and diagonal of rectangle whose sides have width a and length b:

The perimeter of a rectangle

P = 2(a + b)

The area of a rectangle

A = ab

The diagonal of a rectangle

D = √a^{2} + b^{2}

Where:

a, b = the width and length of a rectangle

P = the perimeter of a rectangle

A = the area of a rectangle

D = the diagonal of a rectangle