Find the area, perimeter, and diagonal of a rectangle. Enter the length and width.
Area
— sq units
Length times width.Usage Tip
For a fixed perimeter, area is largest when the rectangle is closest to a square.
THE MATH
area = length × width
diagonal = √(length² + width²)
diagonal = √(length² + width²)
A rectangle has four right angles; opposite sides are equal.
The diagonal splits it into two right triangles, so the Pythagorean theorem gives its length.
The diagonal splits it into two right triangles, so the Pythagorean theorem gives its length.
Area is length times width; perimeter is twice their sum.
The diagonal connects opposite corners.
A rectangle with equal sides is a square.
The diagonal connects opposite corners.
A rectangle with equal sides is a square.