Calculating Board Foot BOARD FOOT: "Board Foot" is a measurement of lumber volume. A board foot is equal to 144 cubic inches of wood. Actually it's easy to calculate using the following formula: (Thickness x Width x Length) / 144 = Board Feet Note: Lumber is specified by its rough size. This is why a 1" board is actually 3/4" thick and called 4/4 and a 1 1/4"  thick board is called 5/4 and actually 1 1/16" and  a 2" board is actually 1-13/16"-+ thick called 8/4. When you are figuring up board feet, keep in mind a waste factor. If you purchase good clear material add about 15% for waste, if you  use lower grade material you will have to allow for defects and more wasted material add about 30%. Do not forget some lumber yards make make a 6" wide board 7" as it call that after clean cut side it removed. Take a few boards and run the measurements and you will see how easy this works.

Lumber is sold by the board foot. A board foot is the unit of measurement for lumber. A board foot is 12 inches long, 12 inches wide and 1 inch thick.

Domestic lumber will come S3S -- Surfaced two sides and one edge straight line ripped. Exotic lumber is S2S (surfaced two sides) only, unless otherwise specified.

Following is standard thickness of surfaced lumber unless otherwise specified:

• Domestic 4/4 or 1" is surfaced to 13/16"
• Domestic 5/4 or 1-1/4 is surfaced to 1-1/16"
• Domestic 8/4 or 2" is surfaced to 1-13/16"
• Exotic 4/4 lumber is S2S 15/16"
• Exotic 8/4 is surfaced to 1-15/16"