Board Feet Formula
A board foot is standard unit of volume equal to a 1-inch thick, 12-inch wide, 1-foot long board ($144 \text{ inches}^3$).
\[\text{Board Feet (single)} = \frac{\text{Thickness (in)} \times \text{Width (in)} \times \text{Length (ft)}}{12}\]When board length is measured in inches:
\[\text{Board Feet (single)} = \frac{\text{Thickness (in)} \times \text{Width (in)} \times \text{Length (in)}}{144}\]\(\text{Total Board Feet} = \text{Board Feet (single)} \times \text{Piece Count}\) \(\text{Total Cost (\$)} = \text{Total Board Feet} \times \text{Price per Board Foot (\$/BF)}\)
Standard Dimensional Lumber Board Feet Table
| Nominal Lumber Size | Length (ft) | Board Feet per Piece (BF) | Pieces per 100 BF | Cost per Board at $5.00/BF |
|---|---|---|---|---|
| 1x6 (0.75” × 5.5”) | 8 ft | 4.00 BF | 25 Pieces | $20.00 |
| 2x4 (1.5” × 3.5”) | 8 ft | 5.33 BF | 19 Pieces | $26.67 |
| 2x6 (1.5” × 5.5”) | 8 ft | 8.00 BF | 13 Pieces | $40.00 |
| 2x8 (1.5” × 7.25”) | 10 ft | 13.33 BF | 8 Pieces | $66.67 |
| 2x10 (1.5” × 9.25”) | 12 ft | 20.00 BF | 5 Pieces | $100.00 |
| 4x4 (3.5” × 3.5”) | 8 ft | 10.67 BF | 10 Pieces | $53.33 |
How to Use This Board Feet Calculator
- Enter Thickness in inches (use nominal fraction like 4/4 = 1”, 8/4 = 2”).
- Enter Width in inches and Length in feet.
- Specify Number of boards needed for your project.
- Input Price per Board Foot ($/BF) supplied by your lumber yard.
- View single piece board feet, total order board feet, piece unit cost, and overall order total.
Frequently Asked Questions
What is a board foot?
A board foot (BF) is a unit of volume for measuring lumber in North America. One board foot represents a piece of wood 1 inch thick, 12 inches wide, and 1 foot (12 inches) long, equaling 144 cubic inches of wood volume.
What is the formula for board feet?
The formula for board feet when length is in feet is: Board Feet = (Thickness in inches × Width in inches × Length in feet) / 12. If length is measured in inches, divide by 144: Board Feet = (Thickness in inches × Width in inches × Length in inches) / 144.
How do you calculate board feet for rough vs dressed lumber?
Rough-sawn hardwood is sold by nominal thickness quarters (e.g., 4/4 = 1”, 5/4 = 1.25”, 8/4 = 2”). Board feet is calculated based on nominal un-surfaced dimensions prior to planing, even though surfaced boards are slightly thinner.
How many board feet are in a 2x4 8 feet long?
A 2x4-8’ board contains 5.33 board feet. Nominal calculation: (2 inches × 4 inches × 8 feet) / 12 = 5.333 BF.
What is the difference between linear feet and board feet?
Linear feet measures only the overall length of a board regardless of width or thickness. Board feet measures 3D volume (length × width × thickness).
How much waste should I add when ordering hardwood lumber?
Woodworkers generally add 15% to 20% waste for rough hardwood lumber to account for defects, knots, wane, and machining loss.
Is my lumber calculation data saved on external servers?
No. All calculation logic executes locally in your web browser.