Board-foot calculator

Enter billing dimensions

In US mode, enter thickness and width in inches and length in feet. Metric mode uses millimeters for the cross-section and meters for length; results remain in board feet. Fractions such as 1 1/4 are accepted. Add a row for each size or price. Enter a price per board foot, not a price per board or per linear foot. A zero price leaves that row’s cost unassigned.

This tool uses exactly the dimensions you enter. It does not turn a nominal 2 × 4 into a measured 1½ × 3½ or infer a dealer’s rough-lumber tally. Use the supplier’s billing basis for a cost estimate; use measured dimensions if you want physical volume. These can differ. Dealer minimums, surface-measure rounding, taxes and delivery are excluded.

Formula and example

One board foot is 144 cubic inches: 1 in × 12 in × 12 in. Per row, board feet = thickness in inches × width in inches × length in feet × quantity ÷ 12. Cost = board feet × entered price per board foot. Totals sum the rows before display rounding.

Example: three 1 in × 6 in × 8 ft boards contain 12 BF. At $5/BF, the base cost is $60. An optional 10% reserve adds 1.2 BF and $6, for 13.2 BF and $66. This extra volume is not a whole-board order or a guarantee of cutting yield.

Independent reference: the University of Alaska lumber grading manual (PDF) explains board-foot measurement. Confirm how your seller tallies the material you are buying.

Plan the actual cuts

Volume alone cannot show whether a long piece fits a board. Use the linear cut-list calculator for lengths, kerf and offcuts, or the equal-spacing calculator for a repeated-piece layout.