Rectangle Perimeter Calculator

Calculate the perimeter and diagonal of a rectangle from its length and width.

Enter length and width.

Rectangle Perimeter Formula

Perimeter = 2(length + width)
Diagonal = √(length² + width²)
Example: l = 12, w = 8
P = 2(12 + 8) = 40 | Diagonal = √(144 + 64) = 14.42

Last updated: 2026-08-08