Metric Unit Calculator
The formula, your substituted values, and the evaluated result are shown below.
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View offerAffiliate link — we may earn a commission at no extra cost to you.Calculate lumber volume in board feet.
This is a planning estimate. Confirm dimensions, allowances, material specifications, applicable codes, and supplier requirements before purchasing or construction.
Calculate lumber volume in board feet.
A board foot is the standard volume unit for hardwood and many lumber sales in North America: a piece 1 inch thick, 12 inches wide and 1 foot long (144 cubic inches). The calculator uses:
Board feet = thickness (in) × width (in) × length (ft) ÷ 12
Note the mixed units: thickness and width in inches, length in feet.
Softwood is sold by nominal size: a "2 × 6" is really about 1.5 × 5.5 inches after drying and planing, but board feet are normally worked out on the nominal 2 × 6. Rough-sawn hardwood is sold in quarters of an inch, so 4/4 ("four quarter") is 1 inch thick and 8/4 is 2 inches. Price per board foot is quoted on those rough dimensions.
One board foot = 144 in³ = 0.00236 m³, so there are about 424 board feet per cubic metre. In Australia, timber is sold by the lineal metre or cubic metre, so convert with that factor when you compare imported timber prices.
Allow 15–25% extra for hardwood furniture projects, to cover defects, grain matching and cutting losses. Rough boards also lose thickness when planed.
2 × 4 × 8 ÷ 12 = 5.33 board feet.
Multiply by 0.00236. For example, 100 board feet is about 0.236 m³.
It prices timber by volume regardless of shape, so boards of different widths and thicknesses can be compared fairly.