Rectangular Prism Diagonal Calculator
Enter the length, width, and height of a rectangular prism to calculate its space diagonal.
Rectangular Prism Diagonal Calculator
Calculate the space diagonal (corner-to-corner distance) of a rectangular box.
This is a straightforward geometric calculation; ensure all three measurements use the same unit.
The space diagonal of a rectangular box (also called a rectangular prism or cuboid) is found using a 3D extension of the Pythagorean theorem, combining the length, width, and height.
Example
- With the default values shown above, this calculator returns: Space Diagonal ≈ 12.3288.
Frequently Asked Questions
What is a space diagonal?
The space diagonal is the longest straight line that can be drawn inside a rectangular box, connecting one corner to the diagonally opposite corner through the interior.
How is this different from a face diagonal?
A face diagonal only crosses one flat face of the box (using two of the three dimensions); the space diagonal cuts through the interior of the box using all three dimensions.