Lumber Board Feet Calculator
Calculate the board feet of lumber from thickness, width, and length. Board feet is the standard lumber volume unit.
How to use this tool
- Enter the nominal thickness, width (in inches), and length (in feet).
- Enter the number of boards you plan to buy.
- The calculator shows board feet per piece and the total for all boards.
Calculate board feet of lumber for any woodworking or construction project.
Formula
Board feet (BF) per board = Thickness (in) × Width (in) × Length (ft) ÷ 12
Total board feet = BF per board × Number of boards
How it works
A board foot is the standard North American lumber volume unit equal to a piece 1 inch thick, 12 inches wide, and 12 inches long (144 cubic inches). This calculator multiplies thickness in inches by width in inches by length in feet, then divides by 12 to convert the product to board feet. Multiplying by the board count gives the total. The formula assumes nominal dimensions as entered; actual (dressed) lumber dimensions are smaller than nominal.
Worked example
Worked example
- Each board: 1 in thick × 6 in wide × 8 ft long; 10 boards total.
- BF each = 1 × 6 × 8 ÷ 12 = 48 ÷ 12 = 4.0 BF.
- Total BF = 4.0 × 10 = 40.0 BF.
Board feet each = 4.0 BF; total board feet = 40.0 BF.
Key terms
- Board foot (BF)
- A unit of lumber volume equal to 144 cubic inches (1 in × 12 in × 12 in); used for pricing and ordering lumber.
- Nominal dimension
- The labelled size of lumber (e.g., 2×4); actual finished size is smaller after milling and drying.
- Thickness
- The smallest cross-sectional dimension of a board, measured in inches.
- Linear foot
- A length measurement of one foot along the board's longest axis, without regard to cross-section.
- Dressed lumber
- Lumber that has been planed smooth after sawing; its actual dimensions are less than its nominal dimensions.
Frequently asked questions
- What is a board foot?
- A board foot is a unit of lumber volume equal to a piece 1 inch thick, 12 inches wide, and 12 inches long (144 cubic inches).
- How do I calculate board feet?
- Multiply thickness (inches) × width (inches) × length (feet) ÷ 12. For example, a 1"×6"×8' board = 1×6×8/12 = 4 board feet.