Lumber Calculator: Board Feet
The lumber calculator takes four inputs: thickness, width, length, and quantity. From those, it returns total board feet, total lineal feet, and a waste-adjusted buy quantity. Contractors, builders, and weekend woodworkers use it to price a lumber order before they load the truck. Enter your dimensions once and see both the volume the yard uses for pricing and the exact piece count to buy.
Plan the lumber order, not just the board feet
Use the answer as a buying checklist before you compare supplier quotes. The important checks are the dimension basis, the waste allowance, and the unit the yard uses for pricing.
Use dressed / actual dimensions for most retail boards. Switch to softwood nominal tally only when the quote or takeoff is written on nominal board-foot basis.
Keep a small waste allowance for straight stock lists and raise it when the layout has short cutoffs, defects, miters, or field changes.
Match the quote unit: dollars per board foot, dollars per lineal foot, or dollars per piece. Do not mix a board-foot total with a piece price.
Use the Decking Calculator for a full deck board takeoff, the Stud Wall Framing Calculator for wall framing, and the Lumber Weight Calculator when the question is load or hauling weight.
Example: 24 nominal 2×6 boards with waste
A plan that calls for 24 nominal 2×6 boards at 10 ft can be priced on nominal tally if the supplier quotes that way. Each board is (2 × 6 × 10) ÷ 12 = 10 BF. Add 10% waste: 24 × 1.10 = 26.4, so the buy count rounds up to 27 boards. The order is 270 board feet; at $2.15/BF, the estimated lumber cost is $580.50.
Should I enter nominal or actual lumber size?
Most dimensional lumber is sold with a nominal name such as 2×6, but the finished board is smaller after drying and surfacing. NIST explains the nominal-versus-actual sizing issue. Use dressed / actual dimensions when you are estimating finished volume or coverage; use softwood nominal tally only when the supplier quote or project takeoff explicitly uses nominal board-foot basis.
How much waste should I add?
For a straight list of repeated boards, 5-10% usually covers reasonable cut loss and culls. Move toward 15% or more when the layout has diagonal cuts, short blocking, visible grain selection, or several lengths that cannot share offcuts. The calculator rounds waste up to whole boards because that is how the order is purchased.
Why do board feet and lineal feet both appear?
Board feet measure volume, so thickness and width matter. Lineal feet measure running length only. A hardwood or rough-lumber quote often uses board feet, while trim, decking, and some retail stock may be quoted by lineal foot or by the piece. Compare the output that matches the quote.
When should I use a different calculator?
Use this calculator for one repeated lumber size. For sheet goods, switch to the Plywood Calculator. For framing walls, use the Framing Calculator or Stud Wall Framing Calculator. For a full deck surface, use the Decking Calculator, which accounts for board coverage, gaps, layout angle, and fasteners.