How to Calculate Cubic Inches

Calculating the Volume of a Box in Cubic Inches

Measure the length, width, and depth of an object in inches. To calculate the volume of a rectangular space, all you need to know are the values of its dimensions in inches. You may need to physically measure the object or to convert to inches from a different set of units. To calculate the volume, you need to use the same unit (inches in our case) for all dimensions, otherwise you won't get the correct result. For example, if we wanted to find the volume of a refrigerator, we would find its length, width, and depth in inches. Let's say our fridge is 50 inches (127.0 cm) long, 25 inches (63.5 cm) wide, and 20 inches (50.8 cm) deep.

Write the length of your object. The first step in calculating a volume with this process is to write one of your dimensions down. You can multiply these dimensions in any order - for our purposes, let's write the length first. In our example, we would write 50 first, as our fridge is 50 inches (127.0 cm) long.

Multiply the length by the width of your object. Next, multiply your first dimension by one of the others. Again, you can multiply your dimensions in any order, but, for our purposes, let's multiply the length by the width. In our example, we would multiply 50 × 25 - the width. 50 × 25 = 1250.

Multiply your answer by the depth of your object. Finally, multiply the answer you got by multiplying two of your object's dimensions by the remaining dimension. In our case, this means multiplying the product of our object's length and width by its depth. In our example, we would multiply 1250 × 20 - the depth. 1250 × 20 = 25,000.

Label your answer in cubic inches. You may know that your final answer refers to a volume in cubic inches, but another person may not. Be sure to use a proper label for your answer that specifies that the volume is in cubic inches. Acceptable labels include: "Cubic Inches" "Inches Cubed" "Cu. In." "In"

Calculating the Volumes of Other Shapes

Calculate the volume of a cube with L. Cubes are rectangular prisms (boxes) in which every side length and angle is equal. Thus, the volume of a cube can be written as length × width × depth = length × length × length = length. To get your answer in cubic inches, ensure your length measurement is in inches.

Calculate the volume of a cylinder with v = hπr. Cylinders are smooth-sided objects with two circular faces of equal size. The formula v = hπr where v = volume, h = height, and r = the cylinder's radius (the distance from the center of either of the circular faces to its edge) gives the volume of a cylinder. Make sure your measurements for h and r are in inches.

Calculate the volume of a cone with v = (1/3)hπr. Cones are smooth-sided objects with a circular base that tapers to a point. The formula v = hπr/3 where v = volume, h = height, and r = the radius of the circular base gives the volume of a cone. As above, ensure your measurements for h and r are in inches.

Calculate the volume of a sphere with v = 4/3πr. Spheres are perfectly round 3-d objects. The equation v = 4/3πr where v = volume and r = the radius of the sphere (the distance from its center to its edge) gives the volume of a sphere. As before, make sure your measurement for r is in inches.