Rectangular Prism Calculator
Find the volume, surface area, and space diagonal of a rectangular prism (cuboid) from its three dimensions.
Inputs explained
- Length — First dimension of the box.
- Width — Second dimension of the box.
- Height — Third dimension of the box.
How to use it
- Fill in the fields above — each input has a hint describing exactly what to enter
- Press Calculate to get your result instantly, right on this page
- Copy the result, save the tool to favorites, or share and embed it anywhere
Understanding the result
Example: A 3 × 4 × 5 box has volume 60, surface area 94, and space diagonal √50 ≈ 7.0711.
Frequently asked questions
What is the space diagonal and why would I need it? The space diagonal is the straight line from one corner of the box to the opposite corner, passing through its interior, calculated as √(length² + width² + height²). It's useful for checking whether an object will fit diagonally through a doorway or into a box.
Is a rectangular prism the same as a cube in this calculator? A cube is just a special case where length, width, and height are all equal; you can get cube results by entering the same value in all three fields.
Is the Rectangular Prism Calculator free to use? Yes — it is completely free, with no sign-up, no download and no usage limits. You can use it as often as you need.
Is my data private? Yes. The calculation runs entirely in your browser — the values you enter are never sent to our servers, stored or shared with anyone.
What information do I need? Just the following: Length, Width, Height. Each field includes a hint explaining exactly what to enter.
Can I use it on my phone? Yes — the tool is fully responsive and works on any device, and the same calculator is available in the EasyWorkCalcs mobile app.
Privacy
Everything you enter into the Rectangular Prism Calculator is processed entirely in your browser. Nothing is uploaded, stored or shared — your data stays on your device.