Lumber Board Foot Cost Calculator
Price rough lumber by the board foot — total board feet for a stack of boards and the cost at a per-board-foot rate.
How it works
board feet = thickness(in) × width(in) × length(ft) ÷ 12 · cost = board feet × price per bf
A board foot is 144 cubic inches of wood — one square foot at one inch thick. With length in feet, the formula is thickness × width × length ÷ 12. Rough hardwood is sold on its nominal quarter thickness (4/4 = 1 in, 8/4 = 2 in) measured before surfacing, so you pay for the full rough board. Multiply the total board feet by the yard’s per-board-foot price for the cost.
Worked example
Ten 4/4 (1 in) × 6 in × 8 ft boards: each is 1 × 6 × 8 ÷ 12 = 4 board feet, so ten are 40 bf. At $4.50 per board foot the stack is $180.
Frequently asked questions
What is a board foot?
The volume of a piece 1 ft × 1 ft × 1 in — 144 cubic inches. It is a volume measure, so a 1×12 and a 2×6 of the same length hold the same board footage. Hardwood lumber is priced this way rather than by the linear foot.
Do I use rough or finished thickness?
Rough (nominal) thickness. A 4/4 board is billed as 1 in even though it planes down to about 13/16 in. You pay for the wood removed in surfacing, which is why buying skip-planed or rough saves money if you have a planer.
How is this different from a 2×4?
Softwood framing like a 2×4 is sold by the piece and linear foot at its finished (smaller) size, not by the board foot. Board-foot pricing is the norm for rough hardwood; use it for furniture and millwork stock, not dimensional framing.
Related calculators
Estimates only — add for waste and confirm against local building codes and supplier specs.