Board Foot Lumber Cost Calculator
The board foot lumber cost calculator helps woodworkers, builders, and hobbyists estimate the volume and cost of lumber for any project. A board foot is the standard US measure of lumber volume: a piece 1 inch thick, 12 inches wide, and 12 inches long. By entering your board's thickness, width, and length, along with the price per board foot and quantity, this calculator gives you total board feet, adjusted board feet with a waste allowance, and the full material cost. Knowing your board foot count before heading to the lumber yard ensures you buy the right amount and stay within budget, whether you are building furniture, shelving, or a deck.
Board foot formula
Board feet = (Thickness (in) x Width (in) x Length (ft)) / 12
Total BF = Board feet per board x Quantity
Adjusted BF = Total BF x (1 + Waste % / 100)
Total cost = Adjusted BF x Price per BF
Length in feet makes the formula cleaner: (T x W x L(ft)) / 12. If length is in inches, use: (T x W x L(in)) / 144.
Frequently asked questions
What is a board foot?
A board foot is a unit of lumber volume equal to a piece of wood that is 1 inch thick, 12 inches wide, and 12 inches long (144 cubic inches or 1/12 of a cubic foot). It is the standard unit of measure for buying and selling lumber in the United States.
How do I calculate board feet?
Board feet = (Thickness in inches x Width in inches x Length in inches) / 144. For example, a board 2 inches thick, 6 inches wide, and 8 feet (96 inches) long is (2 x 6 x 96) / 144 = 8 board feet.
What is the difference between nominal and actual lumber dimensions?
Nominal dimensions are the traditional names for lumber (e.g., 2x4), while actual dimensions are smaller after milling and drying (a 2x4 actually measures 1.5 x 3.5 inches). Board foot calculations are based on nominal dimensions for standard dimensional lumber.
Why do hardwood prices vary so much?
Hardwood lumber prices vary by species, grade, availability, and region. Common hardwoods like poplar or oak may cost $3 to $8 per board foot, while premium species like walnut, cherry, or figured maple can cost $10 to $25 or more per board foot.
Should I add a waste factor when calculating lumber?
Yes. A waste factor of 10 to 20% is standard to account for defects, cuts, and mistakes. For complex projects or figured wood with knots, add 20 to 25%. You can add extra boards to your order or use the waste percentage field to calculate the adjusted quantity.
Sources
- USDA Forest Service: National Forest Timber Program.
- Forest Products Laboratory (USDA): Wood Handbook - Wood as an Engineering Material.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.