Maths & numbers
Rectangle calculator
Calculate area, perimeter and diagonal from two side lengths.
A clear answer. Here’s how.
Area = width × height, perimeter = 2(width + height), and diagonal = √(width² + height²). Use the same length unit for both inputs.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- Width
- 8
- Height
- 5
Example result
- Area (square units)
- 40
- Perimeter
- 26
- Diagonal
- 9.43398113206