BuildMeasureUnderstanding Board Feet
A board foot measures volume: a piece 12 inches long, 12 inches wide, and 1 inch thick contains one board foot. It is different from a linear foot, which only measures length.
The formula
For five boards measuring 1 × 6 × 96 inches, the result is 20 board feet. If your supplier charges 6 currency units per board foot, the base material estimate is 120. With a 10% volume allowance, the estimate becomes 22 board feet and 132 currency units.
Actual dimensions versus nominal sizes
A label such as “2 × 4” is a nominal size and may differ from the measured dimensions of surfaced lumber. Enter actual dimensions to estimate physical volume. A lumberyard may bill rough stock using a different measurement convention; confirm the pricing basis before relying on a purchase estimate.
Using metric measurements
One board foot equals 2,359,737.216 cubic millimetres. Multiply thickness, width, and length in millimetres, then divide by that value. The calculator does this conversion for you.
A quick buying checklist
- Check the supplier’s measurement and pricing method.
- Measure thickness, width, and length in the same unit.
- Allow for defects, trimming, and your project’s grain requirements.
- Round your order to the sizes actually available.