Lumber Cost per Board Foot Calculator
Hardwood lumber in the United States is sold by the board foot, a volume unit equal to 144 cubic inches: a piece 1 inch thick, 12 inches wide, and 12 inches long. To price a project you first convert each board's thickness, width, and length into board feet, multiply by the number of identical boards, then multiply the total footage by the yard's price per board foot. This calculator does all of that, returning board feet per piece, total board feet, and total cost. Enter the thickness your supplier bills you at, normally the rough dimension, and remember to add your own waste allowance on top.
Board foot cost formula
Board feet per piece = (thickness * width * length) / 144
Total board feet = board feet per piece * quantity
Total cost = total board feet * price per board foot
Cost per piece = board feet per piece * price per board foot
All three dimensions are in inches. One board foot is 144 cubic inches, the volume of a 1 by 12 by 12 inch piece.
Buying lumber by the board foot
- Hardwood thickness is quoted in quarters: 4/4 is one inch rough, 8/4 is two inches rough.
- Footage is normally figured on rough dimensions, since surfacing removes material you have already paid for.
- Add a waste allowance, often 20 to 40 percent above net cut-list footage, for defects and trimming.
- Wider and longer boards usually command a price premium that a flat per-board-foot rate does not capture.
- Softwood and dimensional framing lumber are often sold by the linear foot or by the piece instead of by board foot.
Lumber cost: frequently asked questions
What is a board foot?
A board foot is the standard unit for measuring hardwood lumber volume in the United States. One board foot equals 144 cubic inches, the volume of a piece 1 inch thick, 12 inches wide, and 12 inches long. It is a volume measure, so a thick narrow board and a thin wide board of the same volume contain the same board footage.
How do I calculate board feet?
Multiply thickness in inches by width in inches by length in inches, then divide by 144. For length given in feet, multiply thickness times width times length in feet and divide by 12 instead. This calculator uses inches for all three dimensions and divides by 144, then multiplies by quantity.
Should I use nominal or rough thickness?
Hardwood is usually sold by rough thickness expressed in quarters, where 4/4 means one inch rough. Board footage is normally figured on the rough dimensions you are charged for, not the final surfaced size. Enter the thickness the supplier bills you at for an accurate cost.
Why is lumber priced per board foot?
Board foot pricing lets a supplier charge consistently for volume regardless of how a board's thickness, width, and length combine. A wide thick plank and several narrow thin boards that contain the same board footage cost the same at a given price per board foot, which keeps pricing fair across varied stock.
Does this include waste?
No. The calculator returns the cost of the exact board footage you enter. Woodworkers typically add a waste allowance of 20 to 40 percent on top of the net footage in a cut list to cover defects, trimming, and grain matching. Add your own allowance to the dimensions or quantity before pricing.
Official sources
- USDA Forest Products Laboratory: Wood Handbook (lumber grading and measurement).
- Forest Products Society: wood products technical resources.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.