Board Feet Calculator — Lumber
Price hardwood and plan woodworking projects. Add each size of board, its length and quantity, and get the total board feet and cost.
| Thickness (in) | Width (in) | Length (ft) | Qty | Board feet |
|---|
Total board feet
How to calculate board feet
- Enter the thickness and width in inches and the length in feet for each size of board, with how many you need.
- Add a row for each different size.
- Enter your price per board foot and a waste allowance to estimate cost.
What is a board foot?
A board foot is a volume of wood 12 inches by 12 inches by 1 inch thick (144 cubic inches). Board feet = thickness (in) × width (in) × length (ft) ÷ 12. A 1 × 6 board 8 feet long is 4 board feet; a 2 × 4 the same length is about 5.3.
Hardwood is sold by the board foot using rough thickness in quarters of an inch: 4/4 is 1 inch, 5/4 is 1¼, 8/4 is 2 inches. Use the rough (nominal) dimensions for pricing, since that is what the lumberyard charges for, even though the board will be thinner after planing.
Add 15–30% for defects, grain matching and cutting waste, depending on the grade and how picky the project is. Softwood dimensional lumber at home centers is usually sold per piece, not by the board foot.
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Frequently asked questions
How many board feet in a 2×4×8?
About 5.33 board feet (2 × 4 × 8 ÷ 12).
What does 4/4 mean?
Four quarters of an inch: 1 inch rough thickness. 8/4 is 2 inches.
Should I use nominal or actual size?
For hardwood pricing, the rough thickness the yard charges for. For volume of finished stock, use actual dimensions.
How much extra should I buy?
Typically 15–30% depending on lumber grade and how much figure matching the project needs.