Calculate board feet of lumber from thickness (inches), width (inches), and length (feet). Enter quantity to get total board feet for a project.
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Shop Express Tools →Board feet = (Thickness inches × Width inches × Length feet) ÷ 12. One board foot equals a piece of lumber 1 inch thick, 12 inches wide, and 12 inches long — 144 cubic inches total. This is the standard volume unit for buying and selling dimensional lumber.
A board foot is a unit of lumber volume — not length. It accounts for all three dimensions: thickness, width, and length. The formula is:
Lumber is sold in board feet because it comes in many different widths and thicknesses — selling by linear foot alone would be meaningless for pricing purposes. A 1×12 and a 2×6 are both 12 board feet per linear foot, but contain very different volumes of wood. Board feet pricing lets suppliers quote a consistent $/BF rate regardless of the size combination you order.
MBF (thousand board feet) is the standard unit for large lumber orders. If your total is 1,500 board feet, that's 1.5 MBF. Lumber mills and large distributors quote prices in $/MBF. Retail suppliers typically quote in $/board foot or price per piece.
| Nominal Size | Actual Size | BF per Linear Foot | Common Use |
|---|---|---|---|
| 1×4 | 3/4" × 3.5" | 0.33 BF/LF | Trim, furring, sheathing |
| 1×6 | 3/4" × 5.5" | 0.50 BF/LF | Siding, fence boards, trim |
| 1×8 | 3/4" × 7.25" | 0.67 BF/LF | Sheathing, shelving |
| 1×12 | 3/4" × 11.25" | 1.00 BF/LF | Shelving, paneling |
| 2×4 | 1.5" × 3.5" | 0.67 BF/LF | Wall framing |
| 2×6 | 1.5" × 5.5" | 1.00 BF/LF | Floor joists, wall framing |
| 2×8 | 1.5" × 7.25" | 1.33 BF/LF | Floor joists, headers |
| 2×10 | 1.5" × 9.25" | 1.67 BF/LF | Joists, ridge boards |
| 2×12 | 1.5" × 11.25" | 2.00 BF/LF | Heavy joists, beams |
| 4×4 | 3.5" × 3.5" | 1.33 BF/LF | Posts, columns |
| 6×6 | 5.5" × 5.5" | 3.00 BF/LF | Structural posts, decks |
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Start free trialA board foot is a unit of lumber volume equal to a piece 1 inch thick, 12 inches wide, and 12 inches long (144 cubic inches). It's the standard unit for buying and selling lumber.
Board feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12. For a 2×6 that is 10 feet long: (2 × 6 × 10) ÷ 12 = 10 board feet.
Linear feet measures only length, regardless of width or thickness. Board feet measures volume (thickness × width × length). Lumber pricing often uses board feet; flooring often uses linear feet or square feet.