Board Feet Calculator
Calculate board feet for lumber purchases. Enter the board dimensions and the result updates instantly.
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What Is a Board Foot?
A board foot is a unit of volume used for lumber. It equals a piece of wood that is 1 inch thick, 12 inches wide, and 12 inches long — or 144 cubic inches. Hardwood lumber is almost always priced per board foot, making this calculation essential for estimating project costs.
The Formula
Board Feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12
For a standard 1×6×8 board: (1 × 6 × 8) ÷ 12 = 4 board feet. For a 2×4×8: (2 × 4 × 8) ÷ 12 = 5.33 board feet.
Quick Reference Table
| Board Size | Board Feet (8 ft length) |
|---|---|
| 1×4 | 2.67 |
| 1×6 | 4.00 |
| 1×8 | 5.33 |
| 1×12 | 8.00 |
| 2×4 | 5.33 |
| 2×6 | 8.00 |
| 2×8 | 10.67 |
| 4×4 | 10.67 |
Nominal vs. Actual Dimensions
Lumber yard pricing uses nominal dimensions (the name, like "2×4"), not actual milled dimensions (1.5" × 3.5"). When calculating board feet for pricing, use the nominal size. The calculator above works with the dimensions you enter, so enter nominal sizes when estimating cost and actual sizes when calculating true volume.