Board Foot Calculator

Board feet = (thickness in inches × width in inches × length in feet) ÷ 12. The formula uses nominal dimensions. A 2×4 calculates as 2 in × 4 in even though the actual milled size is 1.5 in (3.8 cm) × 3.5 in (8.9 cm). For a 2×4 × 8 ft (2.4 m) piece: (2 × 4 × 8) ÷ 12 = 5.33 BF (~0.0126 m³). The calculator above does this for any size and accepts metric input (cm and m) with m³ equivalents.

A 2×4 × 8 ft (2.4 m) piece is exactly 5.33 board feet: (2 × 4 × 8) ÷ 12 = 64 ÷ 12 = 5.333… BF. At a softwood framing price of $1/BF, that's $5.33 per piece. At $3/BF (Douglas fir, premium grade), $16. The calculator above matches this and lets you set quantity for full bundle pricing. 100 pieces of 2×4 × 8 = 533 BF (~1.26 m³).

Use nominal. That's what lumber yards quote on. A 2×4 is sold as a 2×4 even though the milled size after planing is 1.5 in (3.8 cm) × 3.5 in (8.9 cm). Board foot prices apply to the nominal dimension. The actual size only matters when you're laying out framing or fitting trim. The calculator's preset radio (1×4, 2×6, etc.) uses nominal dimensions. Pick Custom only when working with rough-sawn or specialty stock where you actually want to enter the rough thickness.

Hardwood and rough-sawn softwood: per board foot (BF). Dimensional softwood at big-box stores (Home Depot, Lowe's): per piece, with the per-piece price reflecting BF cost × BF in that piece. Decking and trim: often per linear foot (LF). Multiply LF × the BF per LF for the species to compare. A 2×6 has 1 BF per linear foot, so $4/LF = $4/BF for a 2×6. A 1×6 has 0.5 BF per LF, so $2/LF = $4/BF.

Same formula, but hardwood is often sold by rough size in 4/4 (one inch), 5/4, 6/4, 8/4 thickness rather than nominal 2× sizing. "4/4 oak" means 1-inch (2.5-cm) rough thickness. Calculate as 1 in even though after surfacing it may be 13/16 in (~2.1 cm). For a 4/4 × 6 in × 10 ft oak board (15 cm × 3 m): (1 × 6 × 10) ÷ 12 = 5 BF (~0.0118 m³). The calculator handles this. Pick Custom and enter the rough thickness directly (1 in for 4/4, 1.25 in for 5/4, etc.).

Board feet measure VOLUME, used for lumber pricing because thicker boards have more material. Square feet measure AREA, used for sheet goods (plywood, drywall, flooring). Linear feet measure LENGTH along one dimension, used for trim, baseboard, and cordage. A 2×6 × 8 ft (2.4 m) piece is 8 BF (~0.019 m³), 4 sq ft (0.37 m²) of face area, and 8 LF (2.4 m) of length. Don't confuse them at the lumber yard. If a price says "$/LF" you're paying by the foot of length regardless of thickness.

Price per BF = total price ÷ board feet. If a 2×6 × 12 ft (3.7 m) piece costs $18: BF = (2 × 6 × 12) ÷ 12 = 12 BF (~0.0283 m³), so $18 ÷ 12 = $1.50/BF. The calculator above does the inverse. Enter your $/BF and it gives you total cost. Useful for comparing species: $1.50/BF for pine vs $6/BF for cherry tells you the cherry costs 4× more per equivalent volume, even if a single piece looks similarly priced.

Yes. Pick Metric in the unit selector at the top. Thickness and width switch to centimeters, length to meters. Presets fill international metric SKU dimensions: 2×4 fills 5 × 10 cm (50 × 100 mm), 2×6 fills 5 × 15 cm, and so on. Board feet stays as the primary output (it's an imperial unit and the lumber industry uses it globally), with the m³ equivalent shown in parentheses. 1 BF = 0.00236 m³. Common conversions: 5 cm × 10 cm × 2.4 m = 5.09 BF (≈ 0.012 m³). Your unit choice sticks across pages via localStorage.