Rectangular Prism Calculator
Calculate volume, surface area, and space diagonal of a rectangular prism from its dimensions.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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Request a ToolHow to Use the Rectangular Prism Calculator
Enter the length, width, and height of a rectangular prism (box). The calculator computes the volume, surface area, and space diagonal.
- Enter length, width, and height. All three dimensions are required.
- Read the results. The volume is the primary result. Surface area and space diagonal are shown below.
- Copy or share. Use the buttons to copy or share.
Volume = l * w * h. Surface area = 2(lw + lh + wh). Space diagonal = sqrt(l^2 + w^2 + h^2).
About Rectangular Prisms
A rectangular prism (also called a cuboid or box) is a 3D shape with six rectangular faces. It is the most common solid shape in everyday life: rooms, boxes, books, bricks, and screens are all rectangular prisms. A cube is a special case where all three dimensions are equal. The space diagonal is the longest straight line that fits inside the box, connecting two opposite corners.
Frequently Asked Questions
What is the volume of a rectangular prism?
Volume = length * width * height. For a box that is 10 x 5 x 3, the volume is 150 cubic units.
What is the surface area of a rectangular prism?
Surface area = 2(lw + lh + wh). This accounts for all six faces: two each of length x width, length x height, and width x height.
What is the space diagonal?
The space diagonal connects two opposite corners of the prism, passing through the interior. Its length is sqrt(l^2 + w^2 + h^2), a 3D extension of the Pythagorean theorem.