How this calculation works
The Lumber Board Feet Calculator computes volume in Board Feet (FBM), total Linear Feet, and overall material expenditure for construction framing and fine woodworking hardwoods.
Mathematical formula and logic
Board Feet (1 piece) = (Thickness in × Width in × Length ft) / 12. Total Board Feet = Piece BF × Quantity. Total Cost = Total BF × Cost per BF.
Worked example
Twelve pieces of 2x6 lumber measuring 10 feet long equals (2 × 6 × 10) / 12 = 10 Board Feet per piece. Twelve pieces equal 120 Total Board Feet (120 Linear Feet), costing $540 at $4.50/BF.
Calculation assumptions
- 1 Board Foot equals a volume of 144 cubic inches (1 foot long × 1 foot wide × 1 inch thick).
- Calculations use nominal lumber dimensions for board footage invoicing.
Frequently asked questions
What is a Board Foot (BF)?
A board foot is a specialized unit of volumetric measure for hardwood lumber equal to 1 square foot of 1-inch thick wood (144 cubic inches = 12" × 12" × 1").
What is the difference between nominal and actual lumber sizes?
Nominal lumber is the rough-cut size before drying and planing. A nominal '2x4' has an actual finished dimension of 1.5" × 3.5"; a '2x6' is 1.5" × 5.5".
How do I convert linear feet to board feet?
Multiply Linear Feet by (Thickness in × Width in / 12) = Board Feet.
Why is hardwood priced by the board foot rather than linear foot?
Hardwood logs vary in width and thickness. Pricing by volume (board feet) ensures fair, consistent billing regardless of board width variations.
What does '4/4' or '8/4' lumber mean?
Hardwood sawmills measure thickness in quarters of an inch: 4/4 equals 1 inch thick, 5/4 equals 1.25 inches, and 8/4 equals 2 inches thick.