A board foot is the standard unit hardwood lumber is sold by in North America. One board foot equals a volume of 144 cubic inches — for example a board 1 inch thick, 12 inches wide and 1 foot long. Because boards come in countless thickness/width/length combinations, you can't just compare prices by the piece; you price by the board foot.
Every dimension must be in inches. If your length is in feet, multiply by 12 first (so 8 ft = 96 in). The thickness used is the nominal rough thickness — a board planed from 4/4 (four-quarter) stock is still sold as 1 inch.
| Board | Math | Board feet |
|---|---|---|
| 1″ × 12″ × 1 ft | (1 × 12 × 12 × 1) ÷ 144 | 1.00 bf |
| 2″ × 6″ × 8 ft | (2 × 6 × 96 × 1) ÷ 144 | 8.00 bf |
| 4/4 × 8″ × 10 ft, qty 5 | (1 × 8 × 120 × 5) ÷ 144 | 33.33 bf |
To get cost, multiply board feet by the yard's price per board foot. At $6.50/bf, those 33.33 board feet cost about $216.67.
Hardwood thickness is often quoted in quarters of an inch: 4/4 = 1″, 5/4 = 1.25″, 6/4 = 1.5″, 8/4 = 2″. Enter the decimal inch value (1.25, 1.5, etc.) in the calculator.
The calculator adds a cut list so you can total an entire project's board feet and cost at once, plus a metric input option and a project cost estimator. It runs entirely in your browser — nothing is uploaded, no account needed.