What is the difference between a rectangle and a square?

A square is a special rectangle where all four sides are equal. All squares are rectangles, but not all rectangles are squares.

How do I find the diagonal of a rectangle?

Use the Pythagorean theorem: diagonal = √(length² + width²). For a 6×8 rectangle: diagonal = √(36 + 64) = √100 = 10.

What units does the area come in?

If length and width are in metres, area is in m². If in feet, area is in ft². If in centimetres, area is in cm². The unit of area is always the square of the length unit.

Rectangle Calculator — Area & Perimeter

The Rectangle Calculator computes the area of a rectangle from its length and width. Rectangles are the most common shape in construction, interior design, flooring, and everyday measurement. Knowing the area helps you calculate material quantities — whether you are buying flooring, paint, turf, or tiles.

Length

Width

How to Use This Calculator

1
Enter the length of the rectangle.
2
Enter the width of the rectangle.
3
Click Calculate to see the area.
4
Perimeter = 2 × (length + width). Diagonal = √(length² + width²).

Frequently Asked Questions

Area = length × width. Perimeter = 2 × (length + width). Diagonal = √(length² + width²).

Related Calculators

🧮Triangle Area Calculator 🧮Circle Calculator 🧮Square Footage Calculator