Rectangle Calculator

Calculate the area, perimeter, and diagonal of a rectangle.

Width

Height

Tab to move between fields

Area

Perimeter14

How to Use This Calculator

Start by filling in the input fields below. Results update instantly as you type, so you can experiment with different values to see how they affect the outcome.
Width — enter a numeric value. Minimum value: 0 (default: 4).
Height — enter a numeric value. Minimum value: 0 (default: 3).
Once all inputs are set, review your results in the Results panel. Here's what each output means:
Area — shown as a numeric value. This is the primary result of this calculator.
Perimeter — shown as a numeric value.

How the result changes with Width

Engine last updated July 9, 2026.

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