Calculate the lineal foot factor of a board from the exposed face value.
Knowing the material's lineal foot factor, you can calculate the number of boards needed to cover an area. We use siding as an example, but it can be used for any material with the same exposed face throughout the whole area.
Exposed face = that part of the board you can see when multiple boards are installed. lineal foot factor = 12 inches divided by the exposed face value.
Enter the "exposed face width" in inches and fractions of an inch.
wall length = 10' wall height = 9' exposed face of board= 4 1/2" = 2.67 LFF 10 * 9 * 2.67 = 240.3 lineal feet of board.