Rectangle Area Calculator
Enter the height and width to instantly find a rectangle area, perimeter, and diagonal.
Last updated:
Input
Enter the height and width of a rectangle to calculate its area, perimeter, and diagonal length.
Result
Area
60
Perimeter
32
Diagonal
11.661904
Lengths use the same unit as your input, and the area uses that unit squared.
How it works
- The area is found with height a times width b. If the length unit is cm, the area is in square centimeters.
- The perimeter is found with 2 times (height plus width).
- The diagonal length comes from the Pythagorean theorem as the square root of (height squared plus width squared).
- When the height and width are equal the shape becomes a square, and the same formula still gives the area.
Frequently asked questions
- How is a rectangle's area calculated?
- The area is height a × width b. For example, a height of 4 cm and width of 6 cm give 4 × 6 = 24 cm². The perimeter is 2 × (height + width) and the diagonal is √(height² + width²).
- How does this differ from the square area calculator?
- A rectangle has different height and width and uses height × width. When the two are equal the shape is a square and the same formula applies, but if you only want to enter one side, the square area calculator is more convenient.
- Does it also give the diagonal?
- Yes. The diagonal comes from the Pythagorean theorem as √(height² + width²). For example, a 3 cm by 4 cm rectangle has a diagonal of √(9 + 16) = 5 cm.
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