The number of cubic feet in a standard 20-foot dry goods shipping container is 1,197. In order to calculate cubic feet, it is necessary to know all of the dimensions of the container.
According to Sea Plus, a standard 20-foot shipping container measures 20 feet by 7 feet 9 1/4 inches by 8 feet 6 inches. Cubic feet is calculated by multiplying the total square feet by the height. Square feet is a calculation of width times length. Therefore, essentially, cubic feet is found my multiplying length X width X height. Since the width and height of the container are not even numbers, it is necessary to determine what percentage of a foot the remaining inches are. Once the total number of feet is determined, the numbers are multiplied to find the cubic feet.
The cubic foot measurement for containers used for intermodal shipping were standardized in the 1960s. Typical containers of the time were either 20 feet or 40 feet, and as such, the International Organization for Standardization developed the 20-foot equivalent unit, or TEU, to describe capacity. For example, the capacity of one 20-foot container is equal to one TEU.