Rectangle Calculator
Area, perimeter and diagonal of a rectangle or square.
Area
96cm²
Perimeter
40cm
Diagonal
14.422205cm
Aspect ratio
1.5 : 1
Shape
Rectangle
ShowHide the working
- 1Area = 12 × 8 = 96
- 2Perimeter = 2 × (12 + 8) = 40
- 3Diagonal = √(12² + 8²) = 14.422205
Formula
A = w × h, P = 2(w + h), d = √(w² + h²)How it works
Area, perimeter and diagonal of a rectangle. Equal sides are reported as a square.
Example
12 × 8 gives an area of 96, a perimeter of 40 and a diagonal of 14.42.
About the Rectangle Calculator
Area, perimeter and diagonal of a rectangle or square. It sits in the Geometry section of NWS Calc, a free collection of calculators that run entirely in your browser. There is no signup, no paywall and no tracking — open the page, enter your numbers, get an answer.
Frequently asked questions
- Is the Rectangle Calculator free to use?
- Yes. Every calculator on NWS Calc is completely free, with no signup, no usage limits and no ads.
- Does my data leave my device?
- No. The Rectangle Calculator runs entirely in your browser using JavaScript. Nothing you type is uploaded, logged or stored on a server.
- Can I use the Rectangle Calculator on my phone?
- Yes. The page is fully responsive and works in any modern mobile or desktop browser — there is nothing to install.
- What else is in Geometry?
- Area, perimeter, volume and surface area for every common shape. You can browse the full Geometry category for related calculators.