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.
Select the measurement unit to use
Nominal (rough-sawn) thickness
Shortest dimension of the area
Longest dimension of the area
Number of items needed
Leave blank to skip cost estimate
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
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Last updated: February 2026
All calculations are estimates. Always verify measurements and material quantities before cutting or purchasing.