Lumber Board Foot
Estimate Lumber Board Foot by entering project dimensions. Get material quantities, coverage areas, and cost breakdowns for accurate purchasing and
Formula
Board Feet = (T x W x L) / 12
Multiply thickness (inches) x width (inches) x length (feet), then divide by 12 to get board feet.
Worked Examples
Example 1: Calculate Board Feet
Problem:10 pieces of 2×6×12 lumber.
Solution:Per board:\n(2 × 6 × 12) / 12 = 12 board feet\n\nTotal:\n12 BF × 10 = 120 board feet\n\nAt $0.85/BF:\nCost = 120 × $0.85 = $102
Result:120 board feet, $102 total
Example 2: Compare Lumber Options
Problem:Need 100 BF. Compare: 2×6×10 at $12/piece vs 2×8×12 at $20/piece.
Solution:2×6×10:\nBF = (2×6×10)/12 = 10 BF/piece\nPieces: 100/10 = 10 pieces\nCost: 10 × $12 = $120\n\n2×8×12:\nBF = (2×8×12)/12 = 16 BF/piece\nPieces: 100/16 = 6.25 → 7 pieces\nCost: 7 × $20 = $140\n(7 pieces = 112 BF)
Result:2×6×10 is cheaper: $120 vs $140
Example 3: Deck Framing Estimate
Problem:Deck needs 20 joists (2×8×12) + 2 beams (2×10×16). Calculate total BF.
Solution:Joists:\n(2×8×12)/12 = 16 BF each\n20 × 16 = 320 BF\n\nBeams:\n(2×10×16)/12 = 26.67 BF each\n2 × 26.67 = 53 BF\n\nTotal: 320 + 53 = 373 board feet
Result:373 board feet for framing
Frequently Asked Questions
What is a board foot?
A board foot is 144 cubic inches of lumber (1\" × 12\" × 12\" or any combination equaling 144 cu in). It's the standard unit for pricing and measuring lumber. A 2×6×10 contains 10 board feet: (2 × 6 × 120) / 144 = 10 BF.
How do I calculate board feet?
Formula: (Thickness in inches × Width in inches × Length in feet) / 12. Example: 2×4×8 board: (2 × 4 × 8) / 12 = 5.33 board feet. Multiply by quantity for total. Note: nominal vs actual dimensions don't affect board foot calculation - use nominal.
What are nominal vs actual lumber dimensions?
Nominal (name): 2×4, 2×6, etc. Actual (real): 1.5\"×3.5\", 1.5\"×5.5\". Lumber is planed/surfaced after initial cut, reducing dimensions. Board feet are calculated using nominal dimensions, but building calculations use actual dimensions.
How much does lumber cost per board foot?
Varies widely by species, grade, and market: Framing lumber (SPF): $0.50-2.00/BF. Hardwoods (oak, maple): $3-12/BF. Premium (walnut, cherry): $8-20/BF. Prices fluctuate with market conditions. Always check current local pricing.