Volume is the amount of three-dimensional space taken up by an object. The computer or phone you're using right now has volume, and even you have volume. Finding the volume of a rectangular prism is actually really easy. Just multiply the length, the width, and the height of the rectangular prism. That's it! This article will walk you through the process step-by-step and show you an example.

Steps

  1. 1
    Find the length of the rectangular prism. The length is the longest side of the flat surface of the rectangle on the top or bottom of the rectangular prism.[1]
    • Ex: Length = 5 in.
  2. 2
    Find the width of the rectangular prism. The width is the shorter side of the flat surface of the rectangle on the top or bottom of the rectangular prism.[2]
    • Ex: Width = 4 in.
    Advertisement
  3. 3
    Find the height of the rectangular prism. The height is the part of the rectangular prism that rises up. Imagine that the height is what stretches up a flat rectangle until it becomes a three-dimensional shape.[3]
    • Ex: Height = 3 in.
  4. 4
    Multiply the length, the width, and the height. You can multiply them in any order to get the same different result. The formula for finding the volume of a rectangular prism is the following: Volume = Length * Height * Width, or V = L * H * W.[4]
    • Ex: V = 5 in. * 4 in. * 3 in. = 60 in.
  5. 5
    State your answer in cubic units. Since you're calculating volume, you're working in a three-dimensional space. Just take your answer and state it in cubic units. Whether you're working in feet, inches, or centimeters, you should state your answer in cubic units.[5]
    • 60 will become 60 in3.
  6. Advertisement

Community Q&A

  • Question
    If l=45, w=15, h=x, how do I find the volume?
    Donagan
    Donagan
    Top Answerer
    You have to know the height. Otherwise, you'd have to say the volume is 675x cubic units.
  • Question
    Can you give me another example? I still don't get it.
    Community Answer
    Community Answer
    Remember that length x width x height. A rectangular prism that is five inches high, ten inches long, and two inches deep will have a volume of 100 square in. 5x10x2=100.
  • Question
    How can I calculate the dimension when I know the volume?
    Community Answer
    Community Answer
    The rectangle's area, times the prism's height vertical to the rectangle, gives the volume; various combinations of dimensions give the same volume, so if you know the volume, and want the dimensions, you will find many sets of dimensions. For example volume 24 could give the length, width, and height of 2, 2, and 6; or 2, 3, 4; or 1, 1, 24; and so on.
Advertisement

About This Article

wikiHow is a “wiki,” similar to Wikipedia, which means that many of our articles are co-written by multiple authors. To create this article, 35 people, some anonymous, worked to edit and improve it over time. This article has been viewed 1,139,488 times.
3 votes - 87%
Co-authors: 35
Updated: March 10, 2023
Views: 1,139,488
Categories: Volume
Article SummaryX

1. Find the length, width, and height of the rectangular prism.
2. Multiply the length, width, and height to get the volume.
3. Write the answer in cubic units.

Did this summary help you?
Advertisement