This equation computes the fractional percentage of a full cord of wood that is made of a single stack of 16 inch lengths of wood where you can specify the length (L) and the height (H) of the stack.

Definition of a full chord of wood

A cord of wood is a standard measure of firewood which is defined to be a tightly stacked pile of wood that is 4 ft. by 4 ft by 8ft -- or 128 cubic feet.

To make the measurement of the stack of wood easier, a cord is usually stacked between straight uprights separated by eight feet, as shown in the picture below, making the calculation a straightforward rectangular volume.

Example of a stack of standard cut firewood

If you have a stack of wood whose lengths have been cut to a commonly used 16 inch length and you measure the stack to be 4 ft high and 6 feet long, this equation will compute the fractional percentage of a full cord to be 0.25.  In other words, a single stack of 16 inch lengths that is 4 ft high and 6 feet long equates to 1/4 of a full cord.

See the picture below.