Lumber Calculator
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What Your Result Means
- Board Feet (bf): The total volume of lumber in your order, measured in the standard unit used by sawmills and hardwood dealers. One board foot equals a piece 1 inch thick, 12 inches wide, and 1 foot long (144 cubic inches).
- Estimated Cost: The board-foot total multiplied by your price per board foot. This is before tax, delivery, and any waste or cutting allowance.
- Per-Piece Volume: Larger or thicker boards contain more board feet each, so fewer pieces may be needed than you expect.
How This Calculator Works
You enter the thickness (inches), width (inches), length (feet), quantity, and optional price per board foot. The tool computes board feet per piece as (thickness × width × length) / 12, multiplies by the number of pieces, and then multiplies by price to estimate cost. It assumes nominal dimensions — actual milled lumber is typically slightly smaller than the stated size.
Quick Questions
What exactly is a board foot?
A board foot is a unit of volume equal to 144 cubic inches — picture a board that is 1 inch thick, 12 inches wide, and 1 foot long. Hardwood lumber is almost always priced per board foot.
Should I use nominal or actual dimensions?
Use the nominal (stated) dimensions when ordering from a supplier, since that is how lumber is sold. Actual dimensions after surfacing are typically ¼″ to ½″ smaller in each direction.
How much extra should I buy for waste?
A common rule of thumb is to add 10–15% to your calculated board footage to account for defects, saw kerf, and off-cuts. Complex projects with many angled cuts may need more.
Does this calculator handle metric units?
Not directly. Board feet are an imperial measure. If you have metric dimensions, convert centimeters to inches (÷ 2.54) and meters to feet (÷ 0.3048) before entering them.
Why does price vary so much by species?
Hardwoods like walnut and cherry cost significantly more per board foot than softwoods like pine or poplar because they grow more slowly and are in higher demand for furniture and cabinetry.
Sources
- Board Foot – Wikipedia (definition, formula, and history of the unit)
- Wood Handbook – USDA Forest Products Laboratory (comprehensive reference on wood properties and measurement)
Method & review
Estimate only. Results reflect your inputs and standard formulas. Double-check important decisions independently.