How To Convert Square Feet To Cubic Feet

To convert square feet to cubic feet, you're going to need to do some measuring. The formula for a square or rectangular object's cubic feet is its length times width times height, or:

\(\text{volume}=LWH\)

You might use this formula to figure out how many cubic feet of soil to buy for your garden, for example, or to determine how many ounces of pesticide to use when releasing a bug bomb inside a room of your house.

1. Measure the Extra Dimension

Measure the object's height in feet. (You have already measured the object's length and width to get its measurement in square feet.)

2. Convert Inches to Feet if Necessary

Divide that number by 12 to get its measurement in feet, if you measured the object in inches. If the object is 6 inches tall, it is 0.5 feet.

3. Convert From Square Feet to Cubic Feet

Multiply the object's height in feet by its square foot measurement to convert from square feet to cubic feet. So if you are measuring a garden bed that is 3 feet wide by 6 feet long and 0.5 feet high, its dimensions in cubic feet are:

\(3\text{ ft}\times 6\text{ ft}\times 0.5\text{ ft}=9\text{ ft}^3\)

Note that the size of the garden bed could also be expressed as 18 ft² by 0.5 ft high, and thus calculated as 18 ft² × 0.5 ft, but the result is the same: 9 ft³.