The box industry has a specific way to measure boxes.
First, the measurements should reflect the inside dimensions of the box. The size of the box should be stated in terms of Length, Width and Depth ( or Height ). Length is the longest side of the box. Width is the shortest side. As you look into the opening of the box, the Depth ( or Height ) is the measurement from the opening down to the floor of the box.
A graphic representation of how to measure each box can be found on the box style page. Click on the picture beside the box style description.