Lumber Calculator
Calculate board feet for a single piece of lumber or a whole order using nominal length, width, and thickness.
Total board feet
80bd ft
Per piece
8bd ft
Use nominal dimensions (the size printed on the tag) — a 2x4 is nominally 2 in x 4 in even though its actual dressed size is 1.5 in x 3.5 in. Most lumber is priced per board foot using nominal size.
How the lumber calculator works
Board feet measure the true volume of a piece of lumber, not just its length. One board foot equals a 1-inch-thick piece that's 12 inches by 12 inches — so a longer, wider, or thicker board is worth more board feet.
Formula: board feet = length (ft) × width (in) × thickness (in) ÷ 12. For a full order, multiply the per-piece board footage by your quantity.
Frequently asked questions
A board foot is a unit of lumber volume equal to a piece 12 inches long, 12 inches wide, and 1 inch thick (144 cubic inches). It's the standard unit lumber yards use to price and sell wood, especially hardwoods and larger dimensional lumber orders.
Use nominal dimensions — the size printed on the lumber tag, like 2x6 or 2x4. A 2x6's actual dressed size is 1.5 in x 5.5 in, but board footage and pricing are calculated from the nominal 2x6 size, not the smaller actual size.
Linear footage only measures length and ignores width and thickness, so it only makes sense for a single fixed size of board (like "how many linear feet of 2x4 do I need"). Board footage measures true volume, which is why it's used when comparing or pricing different lumber sizes against each other.
Work out the board feet for one piece, then multiply by how many pieces you need. This calculator does both steps — enter your quantity to see the total for the full order.