Board Feet / Lumber Calculator — ft, in to board feet, cost
How to use this calculator
Enter lumber dimensions — thickness, width, and length — to calculate board feet. Use Single Piece mode for one board, Multiple Pieces to build a cut list with different sizes, or Common Lumber for preset nominal sizes (2x4, 2x6, etc.) with actual dimensions applied automatically.
Formula: Board Feet = Thickness (in) x Width (in) x Length (ft) / 12. One board foot equals a 1" x 12" x 1' piece of lumber. Nominal sizes use actual dimensions (e.g., 2x4 = 1.5" x 3.5").
Saved Calculations
| Time | Mode | Size | Length | Qty | BF | Cost |
|---|
How to Calculate Board Feet
Board feet (BF) is the standard unit for measuring hardwood lumber volume in North America. One board foot equals a piece 1 inch thick, 12 inches wide, and 1 foot long (144 cubic inches). The formula is: BF = Thickness (in) x Width (in) x Length (ft) / 12. This calculator handles single pieces, multiple cut-list items, and common nominal lumber sizes with automatic actual-dimension conversion.
Nominal vs Actual Lumber Sizes
Dimensional lumber sold at retail uses nominal sizes that differ from actual dimensions after drying and planing. A "2x4" actually measures 1.5" x 3.5", a "2x6" is 1.5" x 5.5", and so on. This calculator automatically applies actual dimensions when using the Common Lumber mode, ensuring accurate board-foot calculations.
Lumber Weight Estimation
Weight is estimated at approximately 35 lbs per cubic foot, typical for kiln-dried softwood (SPF, Douglas Fir). Hardwoods like oak or maple may weigh 40-50 lbs/ft³, while cedar and redwood are lighter at 22-28 lbs/ft³.
