A frustum is the base portion of cone in which the pointy top of the cone has been removed. This truncated cone now has both a flat top. This calculator will determine both the cubic inches, centimeters, ounces and gallons of a truncated cone.

## How To Calculate Cubic Inches Of A Conical Frustum

### Example formula for a frustum which is *8* inches tall with a top diameter of *14* inches and bottom diameter of *9* inches.

Divide the top diameter in half (**14** / 2 = 7) to find the top radius. Divide the bottom diameter in half (**9** / 2 = 4.5) to find the bottom radius.

Then enter your height, bottom radius and top radius into the following formula:

π * height * ((bottom radius *bottom radius) + bottom radius * top radius + (top radius*top radius)) / 3

Just for reference, pi (π) equals 3.141592653.

After you’ve entered the dimensions in our example, the formula should look like this:

3.141592653 * 8 * ((4.5 * 4.5) + 4.5 * 7 + (7 * 7)) / 3

Using this formula, a 14 x 9 x 8 inch frustum equals **844**.0412261060001 cubic inches.

## How To Convert Cubic Inches To Centimeters, Feet, Ounces And Gallons

If we needed to know how many cubic feet, we would divide cubic inches by 1728.

To convert cubic inches to ounces, you would multiply cubic inches by 0.554113.

To convert cubic inches to gallons, you would multiply cubic inches by 0.004329.

To convert cubic inches to centimeters, you would multiply cubic inches by 16.3871