Calculate lumber board feet from thickness, width, length and quantity.
Calculator
Lumber Volume Estimate
Review the main result, supporting measurements, and calculation details.
Board Feet and Cost
Calculation Details
| Metric | Value | Note |
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How to calculate board feet
A board foot is a lumber-volume unit equal to a piece 1 inch thick, 12 inches wide, and 1 foot long. Enter thickness and width in inches, length in feet, and the number of pieces.
board feet = thickness (in) x width (in) x length (ft) / 12 x quantity
Board-foot example
One 1 in by 8 in by 10 ft board contains 6.67 board feet. Ten boards contain 66.67 board feet. With 10% waste, the purchasing estimate is 73.33 board feet; at $4.25 per board foot, estimated lumber cost is $311.67.
Nominal versus actual dimensions
Use the dimensions your supplier uses for pricing. Hardwood may be priced from stated rough thickness and measured width, while surfaced softwood commonly has smaller actual dimensions than its nominal name. Do not mix nominal dimensions with an actual-dimension price basis.
Board feet, cubic feet, and linear feet
Board feet measure volume, not surface area or length. Twelve board feet equal one cubic foot. Linear feet describe only total length and do not account for thickness or width. This calculator reports all three so you can check the order from different views.
US lumber reference
The USDA Forest Service defines one board foot as the volume of a board 1 foot long, 1 foot wide, and 1 inch thick. See its forest-products measurement reference.
Frequently asked questions
Should waste be added before cost?
Yes. The cost result multiplies the waste-adjusted board feet by the entered price per board foot.
Can I use this for decking?
Use this page to compare lumber volume. For piece count, joists, fasteners, and whole-board purchasing, use the deck board calculator.
Does this account for random widths?
Run separate calculations for different dimensions or use an average only when your supplier's tally supports it.