Board Foot
lumber
A unit of lumber volume equal to 144 cubic inches — a board 1 inch thick, 12 inches wide, and 12 inches long.
Board feet measure volume, not length, which is why a 1×12 and a 2×6 of the same length contain identical board footage. Hardwood is priced this way because it is sold in random widths and lengths — you are buying a quantity of wood rather than a number of standard pieces. Softwood dimensional lumber is usually priced per piece instead, since a 2×4×8 is a standard commodity. Note that yards bill rough thickness and commonly round widths up to the next inch, so a board measuring 6.25 inches wide is charged as 7. Both practices are standard under NHLA rules and neither is an error on the invoice.
Formula
BF = (thickness in inches × width in inches × length in feet) ÷ 12
Example
A 1 in × 6 in × 8 ft board is (1 × 6 × 8) ÷ 12 = 4 board feet. At $6/BF for walnut, that board costs $24.
Common mistake
Using actual rather than nominal dimensions. A 2×4 counts as 2 by 4 even though it measures 1.5 by 3.5 — you are paying for the wood as it was sawn, before surfacing removed the difference.
Use the Board Foot Calculator
Convert lumber dimensions into board feet — the unit hardwood is actually priced in — for any thickness, width, length, and piece count.
Open Board Foot Calculator →Related Terms
- Linear Foot — A measurement of length only — one foot along a piece of material, regardless of…