Start with the right measurement
A board foot is a volume convention used for rough-sawn lumber pricing. This calculator keeps thickness, width, length, and quantity visible so you can compare a supplier quote without confusing volume with surface area or structural capacity.
How to use this calculator
- 01Thickness and width: Use nominal or actual dimensions consistently with the supplier quote.
- 02Length: Board length in feet for imperial input or millimetres for metric input.
- 03Quantity and waste: Number of boards and an explicit cutting/defect allowance.
Board feet describe lumber volume. They do not say whether a piece is strong enough, straight enough, or legal for a structural use; those decisions require design and supplier information.
Units: Imperial thickness and width are inches, length is feet. Metric mode accepts millimetres and converts to board feet for comparison.
How the calculation works
Board feet = thickness (in) × width (in) × length (ft) × quantity ÷ 12.Ten boards measuring 2 in × 6 in × 8 ft equal 80 board feet.
Worked examples
Nominal framing stock
- Enter ten boards at 2 in × 6 in × 8 ft.
- One board is 2 × 6 × 8 ÷ 12 = 8 board feet.
- Multiply by 10.
Result: The order contains 80 board feet before any waste allowance.
Metric hardwood
- Enter 50 mm × 150 mm × 2,400 mm and quantity 4 in metric mode.
- The calculator converts each dimension to inches and feet internally.
- Review the converted board-foot total alongside the supplier’s actual dimensions.
Result: The result is a volume estimate; grading, surfaced thickness, and supplier rounding still affect price.
How to measure
- 01Use nominal or actual dimensions consistently for your estimate.
- 02In metric mode, enter thickness and width in mm and length in mm.
- 03Ask whether the quote is based on rough, surfaced, or dressed dimensions.
Common mistakes to avoid
- Confusing board feet with square feet
- Mixing nominal and actual dimensions
- Forgetting quantity or waste
Limits of this estimate
Board-foot pricing and grading practices differ by supplier. This tool measures volume, not structural capacity.
Frequently asked questions
What is one board foot?
A volume equal to a board 1 inch thick, 12 inches wide, and 1 foot long.
Can metric lumber be converted?
Yes. Metric dimensions are converted internally, and the result remains in board feet.