Board Foot Calculator
Board feet of lumber & total cost
Buying hardwood or dimensional lumber? Enter the thickness, width, length and number of boards to get the total board feet — the volume unit lumber is priced in — and the cost at your price per board foot.
What is a board foot?
A board foot is a volume of lumber 1 inch thick, 12 inches wide and 12 inches long — 144 cubic inches. It's how rough and hardwood lumber is sold, because it folds thickness, width and length into a single price. The formula is thickness (in) × width (in) × length (ft) ÷ 12, times the number of pieces.
Board feet vs. linear feet
Linear feet measure only length and ignore the cross-section, so they work only when every board is the same width and thickness. Board feet measure volume, so a 2×12 holds far more board feet than a 1×4 of the same length. Use board feet to price rough lumber, and linear feet to buy trim or a fixed profile by the foot.
Estimating lumber cost from board feet
Hardwood is usually quoted in dollars per board foot, often by thickness in quarters (4/4 is one inch, 8/4 is two). Enter your price per board foot for a project total, and add 10–15% for defects, trimming and snipe so you don't run short on the final cuts.
Board Foot Calculator: frequently asked questions
How do I calculate board feet?
Multiply thickness in inches × width in inches × length in feet, then divide by 12. For several identical boards, multiply by the quantity.
What does 4/4 mean in lumber?
It's rough thickness in quarter-inches: 4/4 is one inch, 5/4 is 1¼ inch, 8/4 is two inches. Hardwood is often priced this way before surfacing.
Are board feet the same as linear feet?
No. Linear feet measure only length; board feet measure volume (thickness × width × length). They match only for a 1×12 board.