Calculate board feet, linear feet, and project cost for lumber — add multiple boards at once.
Enter the thickness (in inches), width (in inches), and length (in feet) for each board in your project. Add as many board types as you need using the "+ Add Another Board" button. Optionally enter a price per board foot to get a total material cost estimate. Click Calculate Board Feet to see your totals instantly.
The diagram above dynamically updates to reflect the dimensions of your first board entry, helping you visualize exactly what's being measured.
Board feet is the standard unit of measure for hardwood lumber in North America — and getting it wrong can cost you real money. A hobbyist building a walnut dining table might need 40–60 board feet, while a contractor framing a small addition could need several hundred. At $5–$15 per board foot for hardwood, a miscalculation of just 10 board feet means $50–$150 wasted or a mid-project run to the lumber yard.
Unlike softwood lumber (sold by the linear foot), hardwood pricing is almost always quoted per board foot. Understanding the difference matters when comparing prices at different suppliers. This calculator also helps you translate rough-cut dimensional lumber (like a 2×4 at 1.5"×3.5" actual size) into accurate board-foot costs — many buyers forget to account for the difference between nominal and actual dimensions.
Whether you're a weekend woodworker, a cabinetmaker quoting a job, or a homeowner buying deck boards, knowing your exact board footage prevents over-buying and budget overruns.
A board foot is a unit of volume equal to a piece of wood 1 inch thick, 12 inches wide, and 12 inches long (144 cubic inches).
For example: a board that is 1" thick, 6" wide, and 8 feet long = (1 × 6 × 8) ÷ 12 = 4 board feet.
For multiple quantities, multiply by the count. Total board feet for a project = sum of all individual board calculations. If you're working in metric, the calculator converts mm to inches and meters to feet before applying the formula.
A board foot is a volume measurement (thickness × width × length) that accounts for the size of the wood in three dimensions. A linear foot is simply the length. A 1"×6" board that's 10 feet long is 10 linear feet but only 5 board feet. Hardwood is almost always sold by board feet; dimensional framing lumber is often sold by linear feet.
Use the actual dimensions, not the nominal name. A 2×4 is actually 1.5 inches thick and 3.5 inches wide. So a 10-foot 2×4 = (1.5 × 3.5 × 10) ÷ 12 = 4.375 board feet. Many people mistakenly use 2" and 4" and end up overestimating by about 52%.
Yes — switch to "Metric" in the dropdown and enter thickness in millimeters, width in millimeters, and length in meters. The calculator converts to imperial units internally and then applies the board-foot formula, giving you results in both systems.
A standard rule of thumb is 10% for clear, straight-grained lumber on simple projects, and 15–20% for figured wood, live-edge slabs, or complex cuts. If you're working with very knotty or defective wood, add up to 25%. This calculator shows your net board footage — multiply by 1.10 to 1.20 to get your purchase quantity.