How the board Foot Calculator works
A board foot is the volume of a board 1 inch thick, 12 inches wide, and 1 foot long. Hardwood dealers price by the board foot because boards come in random widths and lengths, and thickness is quoted in quarters: 4/4 is one inch, 8/4 is two inches.
Board feet = thickness(in) × width(in) × length(ft) ÷ 12
Example: ten 4/4 boards, 6 inches wide and 8 feet long, are 4 board feet each, 40 total. At $6 per board foot the order runs $240.
Frequently asked questions
What do 4/4, 5/4, and 8/4 mean?
Rough-sawn thickness in quarter inches: 4/4 is 1 inch, 5/4 is 1.25, 8/4 is 2. After surfacing, 4/4 finishes near 13/16, but you pay on the rough dimension.
Do I calculate on nominal or actual size?
Board feet use the rough (nominal) dimensions before milling. That is the industry convention and what the dealer's invoice will show.
How much extra lumber should I buy?
Plan 15% to 30% over your cut list for defects, grain matching, and mistakes. Complex projects with careful grain selection sit at the high end.