Enter the number of boards and their thickness, width and length. The calculator gives total board feet, which is how hardwood and much rough lumber is priced, and the cost if you enter a price per board foot.
Board feet calculator
How it works
A board foot is 144 cubic inches: a piece 1 in thick, 12 in wide and 1 ft long.
- Board feet = thickness (in) × width (in) × length (ft) ÷ 12 × number of boards
Hardwoods are measured with nominal (rough) thickness in quarters: 4/4 is 1 in, 5/4 is 1-1/4 in, 8/4 is 2 in. Softwood dimension lumber is figured on nominal sizes too: a 2×4 counts as 2 × 4 in even though it is 1-1/2 × 3-1/2 in.
Worked example
Ten 4/4 boards, 6 in wide and 8 ft long:
- Number of boards: 10
- Thickness: 1 in
- Width: 6 in
- Length: 8 ft
- Price per board foot (optional): $0
The calculator gives:
- Board feet: 40.00 BF
- Per board: 4.000 BF
- Volume: 3.333 cu ft (0.0944 m³)
1 × 6 × 8 ÷ 12 = 4 board feet each, so 40 board feet for the ten.
Notes and limits
- Rough hardwood is usually sold by board feet of rough lumber; planing and ripping reduce the usable volume.
- Random-width hardwood is tallied board by board. Enter the average width only for a rough estimate.
- For dimension lumber priced per piece, see the lumber cost calculator.
Frequently asked questions
How many board feet is a 2x4x8?
2 × 4 × 8 ÷ 12 = 5.33 board feet (on nominal sizes).
How many board feet in a 2x6x10?
2 × 6 × 10 ÷ 12 = 10 board feet.
How do you calculate board feet?
Multiply thickness in inches by width in inches by length in feet, and divide by 12.
Sources
- USDA Forest Products Laboratory, Wood Handbook: Wood as an Engineering Material (FPL-GTR-282), board foot and lumber size definitions
- American Softwood Lumber Standard, NIST Voluntary Product Standard PS 20 (nominal and minimum dressed sizes of softwood lumber)
Last reviewed: 25 September 2026. The calculation is covered by automated tests with known answers taken from the sources above. Found an error? Please let us know.