Skip to main content
Skip to main content

What is Volume of a Rectangular Prism?

3D illustration of a rectangular prism showing length, width, and height with cubes filling the inside to represent volume
Understanding volume as space occupied by a 3D shape

Volume tells us how much space is inside a 3-dimensional shape. For a rectangular prism (also called a rectangular box or cuboid), volume measures how much the shape can hold.

Think of a rectangular prism as a box with six rectangular faces. It has three dimensions: length, width, and height.

We measure volume in cubic units like cubic centimeters (cm³) or cubic inches (in³). One cubic centimeter is the space taken by a cube that's 1 cm long, 1 cm wide, and 1 cm high.

Understanding volume helps us solve real-world problems like:

  • How much water fits in a fish tank
  • How many books fit on a bookshelf
  • How much soil is needed to fill a garden bed

How to Calculate Volume

Diagram showing how to calculate volume by multiplying length × width × height
Visual guide to the volume calculation process

Calculating the volume of a rectangular prism is simple once you know the formula:

Volume Formula

V = l × w × h

Where:
V = Volume
l = Length
w = Width
h = Height

Another way to think about it:

Alternative Formula

V = B × h

Where:
B = Base Area (length × width)
h = Height

Let's practice with an example:

Example: Find the volume of a rectangular prism that is 8 cm long, 5 cm wide, and 3 cm high.
Step 1: Identify the dimensions → l = 8 cm, w = 5 cm, h = 3 cm
Step 2: Multiply length × width × height → 8 × 5 × 3
Step 3: Calculate the result → 120 cubic centimeters (cm³)

So the volume is 120 cm³. That means 120 cubes of 1 cm³ each would fit inside this prism.

Real-World Examples

Collage of everyday rectangular prisms: cereal box, building blocks, bookshelf, fish tank
Common objects that are rectangular prisms

Let's practice volume calculation with some real-world examples:

Example 1: Cereal Box

Length: 20 cm
Width: 8 cm
Height: 30 cm

Volume = 20 × 8 × 30 = 4,800 cm³

Example 2: Fish Tank

Length: 60 cm
Width: 30 cm
Height: 40 cm

Volume = 60 × 30 × 40 = 72,000 cm³

(That's 72 liters of water!)

Example 3: Classroom

Length: 10 m
Width: 8 m
Height: 3 m

Volume = 10 × 8 × 3 = 240 m³

Example 4: Pencil Case

Length: 18 cm
Width: 6 cm
Height: 4 cm

Volume = 18 × 6 × 4 = 432 cm³

Volume Practice Quiz

Test your volume calculation skills with this 5-question quiz. Choose the correct answer for each question.

1. What is the volume of a rectangular prism with length 4 cm, width 3 cm, and height 5 cm?
2. How many cubic units are in a rectangular prism that is 3 units long, 2 units wide, and 4 units high?
3. If a rectangular prism has a base area of 25 cm² and a height of 6 cm, what is its volume?
4. Which measurement tells us how much space is inside a rectangular prism?
5. What is the volume of a cube with sides that are each 3 cm long?

Frequently Asked Questions

Here are answers to common questions about volume of rectangular prisms:

Volume Trivia

Discover interesting facts about volume and measurement:

Copyright © 2025 Workybooks. Made with ♥ in California.