Rectangular Prism Calculator
Enter the length, width and height of a rectangular prism (also called a cuboid) to compute its volume, surface area, space diagonal and face diagonals, with the formula shown for each.
Enter dimensions
Enter length, width and height.
Rectangular prism formulas
Volume: V = l · w · h
Surface area: A = 2(lw + lh + wh)
Space diagonal: d = √(l² + w² + h²)
Face diagonals: d_lw = √(l² + w²), d_lh = √(l² + h²), d_wh = √(w² + h²)
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Frequently asked questions
Yes. "Cuboid" is another name for a rectangular prism — a six-faced solid where every face is a rectangle and opposite faces are parallel and equal.
A cuboid has 6 rectangular faces, and each face has one diagonal — so 12 face diagonals in total, arranged as 3 pairs of 4. The lengths are the same within each pair, giving the three distinct face diagonal values reported here.