Board foot calculator
Work out board feet for any number of boards, and the cost when lumber is priced per board foot.
How to use it
Enter each board's thickness and width in inches, its length in feet, and how many pieces you have. Add the price per board foot if your lumberyard quotes one. Hardwood and rough-sawn lumber are usually sold this way.
How it's calculated
A board foot is a piece of wood 12 in × 12 in × 1 in, which is 144 cubic inches.
Board feet = thickness (in) × width (in) × length (ft) ÷ 12
| Board | Board feet per piece |
|---|---|
| 1 × 6, 8 ft | 4 |
| 1 × 12, 10 ft | 10 |
| 2 × 4, 8 ft | 5.33 |
| 2 × 6, 8 ft | 8 |
| 2 × 10, 12 ft | 20 |
| 4/4 × 8 in, 8 ft (hardwood) | 5.33 |
Nominal or actual size?
Board feet are normally calculated from nominal sizes. A 2 × 4 counts as 2 × 4 in, even though it actually measures 1½ × 3½ in once dried and planed. Hardwood is sold in quarters: 4/4 is 1 in thick, 5/4 is 1¼ in, 8/4 is 2 in, measured rough before planing.
If your supplier prices by actual size, enter the actual dimensions instead.
Tips
- Board feet vs linear feet: big-box stores usually price construction lumber per piece or per linear foot (length only). Board feet matter mostly for hardwoods and lumberyards.
- Buy 15 to 20% extra hardwood for knots, checks and cuts, more for figured or wide boards.