WoodCalcs.uk
Board Feet Calculator — Calculate Lumber Board Footage
Calculate board feet from timber dimensions. Enter thickness, width, and length to get board footage for lumber purchasing.
How We Calculate This
This calculator uses the standard board feet formula used by timber merchants and sawmills worldwide.
The formula
Board Feet = (Thickness × Width × Length) ÷ 144
Where thickness and width are in inches, and length is in inches. When length is in feet, the formula becomes:
Board Feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12
Metric conversion
If you enter measurements in millimetres, the calculator first converts to inches (÷ 25.4 for thickness and width, ÷ 304.8 for length in feet) before applying the formula.
Cost estimate
If you enter a price per board foot, the calculator multiplies the total board footage by your unit price to give an estimated material cost.
Frequently Asked Questions
A board foot (BF) is a unit of volume used to measure lumber. One board foot equals a piece of wood 12 inches long, 12 inches wide, and 1 inch thick — equivalent to 144 cubic inches or approximately 2,360 cm³. Hardwood timber is commonly sold by the board foot.
One board foot equals 0.00236 cubic metres (m³) or 2.36 litres. To convert board feet to cubic metres, multiply by 0.002360. This calculator does the conversion automatically.
Board footage is always calculated from the nominal (rough-sawn) dimensions, not the finished size after planing. A board sold as 1-inch thick (25mm) will measure less after surfacing — typically 20–21mm — but you still pay for the full board foot.
UK hardwood prices vary widely. As a rough guide, European oak is typically £8–15 per board foot, American walnut £10–18 per BF, and cherry £7–12 per BF. Prices depend on grade, figure, and supplier. Always get current quotes from your timber merchant.
These are quarter fractions of an inch. 4/4 means 4 quarter-inches = 1 inch (25mm). 8/4 = 2 inches (50mm). 6/4 = 1.5 inches (38mm). This is how rough-sawn hardwood thickness is specified in the trade.
Related Calculators
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Estimate the weight of timber based on species and dimensions.
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Last updated: February 2026
All calculations are estimates. Always verify measurements and material quantities before cutting or purchasing.