Board Feet Calculator
Calculate board feet and lumber cost from length, width and thickness with this free board feet calculator in your browser.
Enter Values
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Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter thickness (inches), width (inches) and length (feet).
- Optionally set the number of boards.
How it works
Board feet = thickness(in) × width(in) × length(ft) ÷ 12, multiplied by the number of boards. One board foot is 144 cubic inches.
Worked example
1 in × 6 in × 8 ft. = 4 board feet.
Common mistakes
- Mixing units — thickness and width are in inches, length is in feet.
- Using nominal sizes (a '1×6' is actually ~¾ × 5½ in dressed timber).
Frequently asked questions
What is a board foot?
A volume of timber equal to 144 cubic inches — a piece 12 × 12 × 1 inch. It is the standard way hardwood is priced in North America.
How do I calculate board feet?
Board feet = thickness (in) × width (in) × length (ft) ÷ 12. The tool handles multiple boards and unit conversions.
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Cite this tool
Zerdly. (2026). Board Feet Calculator. Retrieved from https://www.zerdly.com/tools/board-feet-calculator/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.