Board Feet Calculator
Calculate board feet for rough or dimensional lumber from nominal dimensions and quantity. Enter all dimensions consistently and compare the result with the supplier’s quote.
How this calculator works
A board foot is a volume unit equal to a piece of wood 1 inch thick, 12 inches wide, and 1 foot long (144 cubic inches). It is commonly used for rough lumber and hardwood pricing. Enter thickness and width in inches and length in feet; the calculator multiplies the per-piece volume by your piece count.
board feet per piece = thickness (in) × width (in) × length (ft) ÷ 12 total board feet = board feet per piece × number of pieces
Worked example
One 1 in × 6 in × 8 ft board contains 1 × 6 × 8 ÷ 12 = 4 board feet. Ten boards of those dimensions total 40 board feet.
Nominal and actual lumber dimensions differ
Dimensional lumber is often sold by nominal size while its finished actual dimensions are smaller. Rough lumber may be sold and priced using different conventions. Confirm with the supplier which dimensions and board-foot rules apply to the material you are buying, especially when comparing surfaced and rough stock.
The estimate does not include yield or waste
Board feet are a volume calculation, not a cut list or finished-project quantity. Defects, kerf, planing, grain matching, and offcuts can reduce usable yield. Add project-specific material for waste separately and verify the supplier’s unit pricing before placing an order.
Frequently asked questions
How do you calculate board feet?
Multiply thickness in inches by width in inches by length in feet, then divide by 12. Multiply by the number of pieces for the total.
How many board feet are in a 2×4?
Using nominal dimensions, a 2×4 that is 8 feet long calculates to 2 × 4 × 8 ÷ 12 = 5.33 board feet. Actual dimensions and supplier pricing conventions may differ.
Should I use nominal or actual lumber dimensions?
Use the dimensions specified by the supplier or pricing method you are comparing. Nominal and actual sizes differ for many products, and rough lumber may use additional rules.
Does the result include cut waste?
No. It is the total geometric lumber volume for the dimensions and piece count entered. Add separate stock for defects, cuts, and project waste.