Conversions & Core
Board Foot Calculator
Board feet from lumber thickness, width and length — and the price for the stack.
Inputs
Results
Adjust the inputs to see your result.
About this calculator
Hardwood lumber is priced by the board foot — a volume unit, not a length — which makes yard pricing hard to sanity-check. This calculator converts your board dimensions into board feet, totals a cut list, and prices it at the yard rate.
What this number means
A board foot is a volume pretending to be an area: a piece of wood 1 in thick, 12 in wide and 12 in long — 144 cubic inches. Hardwood yards price by it because it captures what a length price cannot: a wide, thick board contains several times the wood of a narrow one the same length.
That is also why board-foot quotes confuse people at the yard counter. A $6/bf price on a 1 × 6 × 8 ft board ($24 of wood) sounds different from the per-board figure, and the calculator shows both — board feet per board, the stack total, and the money — so a quote in either language can be checked.
The formula
- Board feet per board = Thickness (in) × Width (in) × Length (ft) ÷ 12
- Total board feet = Board feet per board × quantity
- Cost = Total board feet × price per board foot
- Cross-check: one board foot = 144 cu in, so board feet = total cubic inches ÷ 144
Worked example
Ten boards of 1 × 6, eight feet long.
- Per board = 1 × 6 × 8 ÷ 12 = 4 board feet
- Stack total = 4 × 10 = 40 board feet
- At $6 per board foot: $240 for the stack, $24 per board
Assumptions and limitations
- Yards typically tally board feet on nominal (rough) dimensions before surfacing: a surfaced 1×6 (actually 0.75 × 5.5 in) is commonly billed as a full 1 × 6. Enter the size the yard bills, not the size you measure, when checking a quote.
- Rough lumber is sold in random widths and lengths at many hardwood dealers; the tally is per piece. Measure each piece and add the board feet individually for those stacks.
- Softwood construction lumber (2×4, 2×6) is normally priced per piece or per linear foot, not per board foot — this calculator is aimed at hardwood and yard-priced stock.
- Waste for milling (jointing, planing, ripping to final parts) is real: furniture projects typically buy 20–30% more board feet than the finished parts contain. Add that margin to the quantity before pricing a project.
Frequently asked questions
Multiply thickness in inches by width in inches by length in feet, then divide by 12. A 2 × 4 × 8 ft stud, for example, is 2 × 4 × 8 ÷ 12 = 5.33 board feet. The calculator also totals a stack and prices it.
Because yards bill on nominal dimensions. A surfaced board sold as 1×6 measures 0.75 × 5.5 in (3.67 bf at 8 ft by true volume) but is tallied as 1 × 6 — 4 bf. The difference is the surfacing loss, and it is standard practice, not an error.
5.33 board feet at nominal size. Construction lumber is rarely sold by the board foot, but the conversion is handy for comparing bulk softwood prices against hardwood-yard pricing.
Quarters of an inch of rough thickness: 4/4 is 1 in rough (about 0.75–0.8 in surfaced), 5/4 is 1.25 in, 8/4 is 2 in. Enter the rough (nominal) thickness in the calculator when the yard bills that way — which is most of the time.
Add 20–30% beyond the finished parts' board feet for milling waste, defects and grain matching — more for figured or highly selected stock. Compute the project's net board feet, then divide by 0.75 to get a sensible buy quantity at 25% waste.