Calculate the board footage of lumber for your woodworking projects. Add multiple boards and estimate total cost.
Essential tools for measuring and marking lumber accurately.
As an Amazon Associate, WorkshopCalc earns from qualifying purchases. Product recommendations are selected to complement your lumber calculations.
Board feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12. For example, a board that's 1" thick, 6" wide, and 8' long = (1 × 6 × 8) ÷ 12 = 4 board feet.
Lumber thickness is often expressed in quarters of an inch. 4/4 (four-quarter) means 4 quarters or 1 inch thick rough. After surfacing (S2S), it's typically about 13/16" or 0.8" thick. 8/4 is 2 inches rough, about 1.75" surfaced.
Rough lumber is cheaper per board foot and gives you more control over final thickness. However, you need a jointer and planer. Surfaced lumber (S2S or S4S) costs more but is ready to use. For beginners or those without surfacing equipment, S4S is convenient.
Plan for 15-20% extra for waste, defects, and cutting errors. For complex projects with many angled cuts, consider 25-30% extra. It's always better to have leftover wood than to run short mid-project.