Board foot calculator
Add up board feet and cost for a whole lumber order. Thickness accepts quarter notation (4/4, 5/4, 8/4), fractions or decimals.
| Qty | Thickness (in) | Width (in) | Length | Unit | Board feet |
|---|---|---|---|---|---|
Total: 23.96 board feet (0.0565 m³)
With 20% waste allowance: 28.75 BF
The board foot formula
board feet = thickness (in) × width (in) × length (ft) ÷ 12, or with every dimension in inches, ÷ 144. One board foot is 144 cubic inches — a board 1 inch thick, 12 inches wide and 12 inches long.
Board feet of common sizes
| Board | 6 ft | 8 ft | 10 ft | 12 ft |
|---|---|---|---|---|
| 4/4 × 4 in | 2.00 | 2.67 | 3.33 | 4.00 |
| 4/4 × 6 in | 3.00 | 4.00 | 5.00 | 6.00 |
| 4/4 × 8 in | 4.00 | 5.33 | 6.67 | 8.00 |
| 5/4 × 6 in | 3.75 | 5.00 | 6.25 | 7.50 |
| 6/4 × 6 in | 4.50 | 6.00 | 7.50 | 9.00 |
| 8/4 × 6 in | 6.00 | 8.00 | 10.00 | 12.00 |
| 8/4 × 8 in | 8.00 | 10.67 | 13.33 | 16.00 |
How to use the calculator
- Enter each board. Type quantity, thickness, width and length for every board. Thickness accepts 4/4 notation and fractions.
- Add price and waste. Enter the price per board foot and a waste allowance (20–40% is typical for hardwood).
- Read the total. The calculator shows board feet per row, the total, cubic meters and the cost.
Quoted per thousand board feet, per linear foot or per piece? Convert it with the board foot price calculator. Buying or selling logs? The log board feet calculator compares the Doyle, Scribner and International ¼″ log rules.
Board feet tell you what to pay; they do not tell you how to cut. Plan your cuts with the lumber cut list optimizer and read board feet explained for buying tips.
FAQ
What is a board foot?
A board foot is a volume of wood equal to 144 cubic inches: a piece 1 inch thick, 12 inches wide and 12 inches long. Hardwood lumber is priced per board foot.
How do I calculate board feet?
Multiply thickness (in) × width (in) × length (ft) and divide by 12. With all three in inches, divide by 144. For example, a 4/4 board 6 inches wide and 8 feet long is 1 × 6 × 8 ÷ 12 = 4 board feet.
What does 4/4, 5/4 and 8/4 mean?
Hardwood thickness is given in quarters of an inch of rough lumber: 4/4 is 1 inch, 5/4 is 1 1/4 inches, 6/4 is 1 1/2 inches and 8/4 is 2 inches. Type 4/4 or 8/4 straight into the calculator.
How much extra lumber should I buy?
Allow 20–40% for hardwood projects to cover defects, grain matching and milling losses — more for figured or lower-grade boards. Set it in the waste allowance box.