One board foot, defined
A board foot is a volume: 1 inch thick × 12 inches wide × 12 inches long. The formula follows — thickness (in) × width (in) × length (ft) ÷ 12, or ÷ 144 when the length is in inches. It exists because lumber comes in every shape; pricing by volume puts a 10-foot 1×4 and a 5-foot 2×4 on the same scale.
Nominal vs actual — the part that trips everyone
A surfaced 2×4 really measures 1.5 × 3.5 inches, yet board footage for dimensional lumber is customarily figured on the nominal 2 × 4. Rough hardwood runs on the quarter system: thickness is tallied at the standard quarter size — 4/4 counts as 1" even when the rough board's caliper reads a hair over — and width and length follow the yard's tally rules. Neither convention is wrong — they're different markets — but mixing them up changes your bill, so use the quarter buttons above for rough hardwood and ask how the seller figures it.
Pricing an order
Hardwood dealers quote dollars per board foot. Total bf × price = the damage: ten 6-inch-wide 4/4 boards at 8 feet are 40 bf — $260 at $6.50/bf. Add 10–15% over your cut list for defects, checking and mistakes; nobody has ever regretted the extra board.
FAQ
2×4×8 in board feet?
5.33 bf (nominal).
The formula?
T(in) × W(in) × L(ft) ÷ 12 — or ÷ 144 with inches.
4/4 means?
Thickness in quarter inches: 4/4 = 1", 8/4 = 2", rough-sawn.
Cost math?
Total bf × price per bf; the calculator includes it.
Nominal or actual?
Nominal for dimensional lumber; standard quarter thickness (4/4 = 1") for rough hardwood — not your caliper reading.