About Board Feet
A board foot is a unit of volume for lumber equal to 1 foot × 1 foot × 1 inch (144 in³). It's commonly used in North America to price and measure lumber. This calculator accepts both imperial and metric inputs — metric values are converted to inches internally before calculation.
Formula
Board Feet = (Thickness (in) × Width (in) × Length (ft)) / 12 which is equivalent to (T (in) × W (in) × L (in)) / 144.
Points to consider
- Nominal vs Actual Size: Lumber nominal sizes (e.g., 2×4) are not the actual dimensions — use measured actual dimensions for accurate results.
- Moisture & Shrinkage: Wood dimensions change with moisture. Seasoned lumber is smaller than green lumber.
- Waste Factor: Add 5–15% depending on cuts, defects, and joinery waste.
- Ripping / Edging: If you plane or rip boards, remember that final dimensions change board feet counts.
- Rounding: Lumber sellers sometimes round board feet for pricing — discuss rounding rules if buying material.
Example
A single board 2 in × 8 in × 10 ft: (2 × 8 × 10) / 12 = 13.333 BF. Ten such boards = 133.33 BF.