How to calculate board feet
Multiply thickness by width in inches and length in feet, then divide by 12. For several identical boards, multiply by the number of pieces. This calculator does that for every row and adds them up, and the 3D view stacks the boards to scale.
| Board | Board feet |
|---|---|
| 2×4, 8 ft | 5.33 |
| 2×6, 8 ft | 8 |
| 2×8, 12 ft | 16 |
| 2×10, 12 ft | 20 |
| 4/4 × 6 in, 8 ft | 4 |
| 8/4 × 8 in, 10 ft | 13.33 |
Hardwood thickness in quarters
| Quarters | Rough thickness |
|---|---|
| 4/4 | 1 in |
| 5/4 | 1 1/4 in |
| 6/4 | 1 1/2 in |
| 8/4 | 2 in |
| 12/4 | 3 in |
Pricing tips
Hardwood dealers quote a price per board foot for each species and grade. Construction lumber is usually sold per piece, but board feet still help compare prices between yards and work out the cost of a project.
Questions people ask
What is a board foot?
A board foot is a volume of wood 1 in thick, 12 in wide and 12 in long, or 144 cubic inches. Board feet = thickness (in) × width (in) × length (ft) ÷ 12.
Do I use nominal or actual sizes?
Lumber yards price softwood like 2×4s on nominal size, so use 2 and 4 rather than 1 1/2 and 3 1/2. Rough hardwood is sold by its thickness in quarters: 4/4 is 1 in, 8/4 is 2 in. You can type 8/4 directly.
How many board feet are in a 2×4×8?
A 2×4 that is 8 ft long is 2 × 4 × 8 ÷ 12 = 5.33 board feet.
How much extra wood should I buy?
Add 15–20% for rough hardwood, which loses wood to defects, planing and cutting, and 5–10% for dimensional lumber.