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Rectangular Prism Calculator

Calculate the volume, surface area, space diagonal, face diagonals, and lateral area of any rectangular prism (box shape). Enter the length, width, and height for instant results.

A rectangular prism (also called a rectangular cuboid or simply a box) is a 3D solid with six rectangular faces, all angles being 90 degrees.

Key Formulas:

  • Volume: V = length x width x height
  • Surface Area: SA = 2(lw + lh + wh)
  • Space Diagonal: d = sqrt(l² + w² + h²)
  • Lateral Surface Area: LA = 2h(l + w) (just the four sides, no top or bottom)

Example:

A box that is 5 x 3 x 4:

  • Volume = 60 cubic units
  • Surface Area = 2(15 + 20 + 12) = 94 square units
  • Space diagonal = sqrt(25 + 9 + 16) = sqrt(50) = 7.071 units

Practical Uses:

  • Shipping: Volume tells you capacity, surface area tells you how much wrapping or cardboard you need
  • Construction: Concrete volume for foundations, paint for walls (lateral area)
  • Storage: Whether an object fits inside a box (check the space diagonal for long items)
  • Aquariums: Volume determines water capacity; 1 gallon = 231 cubic inches

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