Board Feet From Dimensions Calculator
Turn a board’s thickness, width and length into board feet and total cost — the volume unit lumberyards actually price by.
How it works
Board feet = (thickness in × width in × length in) ÷ 144 · Cost = board feet × price per bf
A board foot is a volume measure — 144 cubic inches, i.e. a piece 1″ thick, 12″ wide and 12″ long. Hardwood is sold by the board foot rather than by the linear foot because it comes in random widths and thicknesses, so a flat per-foot price would be meaningless. Multiply thickness, width and length in inches and divide by 144 to get the volume; multiply by the yard’s per-bf price for the cost. Note that lumber is priced on its rough (nominal) size before surfacing, so a board planed to 3/4″ is usually billed as 4/4 (a full inch).
Worked example
One board 3/4″ thick, 6″ wide and 96″ long: 0.75 × 6 × 96 = 432 cubic inches, ÷ 144 = 3.000 board feet. At $5 per board foot that board costs $15.00. Ten of them would be 30 board feet, or $150.00.
Sources: Board foot — Wikipedia
Frequently asked questions
Do I use the nominal or actual thickness?
Lumberyards charge by the rough (nominal) thickness, so a board surfaced to 3/4″ is usually sold as 4/4 — one full inch. For an accurate cost, enter the thickness the yard is billing you for, not the final planed dimension.
What is the difference between a board foot and a linear foot?
A linear foot is just 12 inches of length regardless of the board’s size. A board foot is a volume — 144 cubic inches — so it accounts for thickness and width too. Use the linear-feet-to-board-feet-calculator to convert between the two.
Why divide by 144?
One board foot is 12″ × 12″ × 1″ = 144 cubic inches. Dividing the board’s volume in cubic inches by 144 converts it to board feet.
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