Our rectangular prism calculator can easily find any parameter about a rectangular prism, including height, length, width, volume, and surface area!

Within a few paragraphs, we will show you:

  • How to find the height of a rectangular prism;
  • How to find the length of a rectangular prism;
  • How to find the width of a rectangular prism; and
  • How to use this tool as a surface area of a rectangular prism calculator.

What is a rectangular prism?

A rectangular prism, is a three-dimensional object with six rectangular sides or faces. Rectangular prisms can be either oblique rectangular prisms (their sides are parallelograms instead of rectangles) or right rectangular prisms (the sides are perpendicular to the bases).

We will work with right rectangular prisms in this rectangular prism calculator.

How to find the surface area of a rectangular prism

This calculator can also find the surface area AA of any rectangular prism!
To manually obtain this value, simply add the area of all the rectangles (faces of the rectangular prism):

A=2hw+2hl+2lwA = 2hw + 2hl + 2lw


  • hh is the rectangular prism height;
  • ww its width; and
  • hh its height.

How to find the volume, diagonal, height, width, and length with the rectangular prism calculator

Now you know how to find the surface area of a rectangular prism, let's look at the other variables.


You can also find the volume of a rectangular prism VV using the same parameters you used in the surface area formula:

V=h×w×lV = h \times w \times l


Similarly, these variables prove themselves useful in finding the diagonal dd of a rectangular prism:

d=l2+w2+h2d = \sqrt{l^{2}+w^{2}+h^{2}}

💡 Does this formula seem familiar? We can obtain this result by using the pythagorean theorem formula!

We can rearrange any of these three formulas (surface area, volume, or diagonal) to solve for ll, ww, or hh based on the information we have.

Alternatively, our rectangular prism calculator can find any missing parameter if you input the others. Give it a try!

Luciano Mino
image of a rectangular prism, with length, height, width and diagonal marked
Length (l)
Width (w)
Height (h)
Surface area
cu in
Diagonal (d)
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