Rectangle Area Calculator
Calculate area, perimeter, and diagonal of a rectangle.
About this calculator
The Rectangle Area Calculator on NumberCals is a free, mobile-friendly tool for anyone needing to calculate area, perimeter, and diagonal of a rectangle. Enter your values in the form below and the result is computed instantly — no sign-up, no installation, no waiting.
Formula used
A = l·w; P = 2(l+w); d = √(l²+w²)
What you'll need
- Length (e.g. 8)
- Width (e.g. 5)
What you'll get
- Area
- Perimeter
- Diagonal
Formula
A = l·w; P = 2(l+w); d = √(l²+w²)
Result
Frequently Asked Questions
What unit is area in? +
Whatever unit you used for length, squared. e.g. m → m².
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