Cubic feet can be visualized as being the number of 12-inch, 3-dimensional cubes that fit within another three dimensional item. Determining how many cubic feet are within an item can help determine the weight of an item and how much can fit within it. Freight and shipping companies use cubic feet to determine the price that an item will cost to ship.
Things You'll Need:
Box being shipped
Ruler or measuring tape
Calculator
Instructions:
Step 1Length and Width. Use a ruler or measuring tape to measure the length of the box you will be shipping. The length, in this case, is the longest side of the box. Determine your length in inches.
Step 2 Measure the width of the box by determining the length of the shorter side of the box.
Step 3Height. Fold the box closed and measure how many inches the box stands from ground to top.
Step 4 Use a calculator and multiply the inches you measured for the length by the inches you measured for the width. Now multiply this by the height of the box. This large number represents the cubic inches of the box.
Step 5 Divide this number by 1,728, the number of cubic inches per cubic feet, to calculate cubic feet for shipping.
Cubic feet can be visualized as being the number of 12-inch, 3-dimensional cubes that fit within another three dimensional item. Determining how many cubic feet are within an item can help determine the weight of an item and how much can fit within it. Freight and shipping companies use cubic feet to determine the price that an item will cost to ship. 
Step 1 Length and Width. Use a ruler or measuring tape to measure the length of the box you will be shipping. The length, in this case, is the longest side of the box. Determine your length in inches.
Step 3 Height. Fold the box closed and measure how many inches the box stands from ground to top.