Lumber Calculator

How to Use This Calculator

Enter your lumber dimensions using the nominal size printed on the board label. For a 2×4, enter 2 for thickness and 4 for width. Length goes in feet. Set quantity to the number of boards in your order. Select your wood species to get an accurate weight calculation: softwood framing lumber (SPF, Douglas Fir, SYP) weighs less per board foot than hardwood. The result shows board feet per piece, total board feet, weight per piece, total weight, and cost if you enter a price. For multiple species or sizes in the same order, calculate each line separately and add the board feet and weights. Lumber yards quote hardwood by the board foot; use this calculator to convert their price into a total order cost.

How to Calculate Lumber Board Feet and Weight

Formula: Board Feet = (Thickness × Width × Length) / 12. Weight = Board Feet × lbs per board foot (by species).

Example: ten 2×4×8 boards of Douglas Fir. Step 1: BF per piece = (2 × 4 × 8) / 12 = 5.33 board feet. Step 2: total BF = 5.33 × 10 = 53.3 board feet. Step 3: weight per piece = 5.33 × 2.6 lbs/BF = 13.9 lbs. Step 4: total weight = 53.3 × 2.6 = 138.6 lbs.

Lumber weight by species per board foot (dry): SPF framing: 2.3 lbs/BF. Douglas Fir: 2.6 lbs/BF. Southern Yellow Pine: 2.7 lbs/BF. Red Oak: 3.8 lbs/BF. Hard Maple: 4.0 lbs/BF. Black Walnut: 3.5 lbs/BF. White Oak: 3.9 lbs/BF.

Note: lumber dimensions are nominal, not actual. Board foot calculations commonly use nominal or rough lumber dimensions, especially when pricing hardwoods and rough-sawn stock. A 2×4 is actually 1.5 × 3.5 inches after milling, but board foot pricing typically uses 2 × 4.

Lumber Tips

Always know the weight before renting a truck. A half-cord of hardwood looks manageable in a pile but weighs over 4,000 lbs. The calculator's total weight output tells you exactly what your load weighs. Half-ton trucks (F-150, Ram 1500) typically have a payload of 1,500 to 2,000 lbs. Three-quarter-ton trucks (F-250, Ram 2500) can handle 2,000 to 2,500 lbs. One-ton trucks (F-350, Ram 3500) often handle 3,000 lbs or more. Check your door placard, which shows the exact limit for your specific truck and configuration.

Buy 10 to 15 percent extra for waste on hardwood projects. Rough-sawn boards need to be jointed and planed flat before use. Twisted, cupped, or bowed boards lose material during milling. Budget 10 percent extra for straight cuts and 15 percent for projects with angled joints or short pieces.

Green lumber weighs 30 to 100 percent more than kiln-dried. Fresh-cut green wood contains free water in the wood cells. A 2×4×8 stud of green lumber can weigh 18 to 20 lbs versus 10 to 12 lbs dry. If you are calculating the weight of a timber-frame delivery of green logs or fresh-sawn lumber, the weight calculator will underestimate unless you know the moisture content.

Order hardwood in the correct rough thickness. Hardwood is sold in quarter-inch increments: 4/4 (1 inch), 5/4 (1.25 inches), 6/4 (1.5 inches), 8/4 (2 inches). Enter the nominal thickness for your quarter-inch designation: for 4/4, enter 1 inch.

What to Buy

For framing and structural work: buy SPF, Douglas Fir, or Southern Yellow Pine (SYP) dimensional lumber from any hardware store or lumber yard. SYP is stronger than SPF for structural applications. Standard lengths are 8, 10, 12, 14, and 16 feet. Priced by the piece at retail, by the unit (bundle) at wholesale.

For hardwood projects (furniture, cabinets, trim): buy from a hardwood dealer or specialty lumber yard. Common species: red oak, hard maple, black walnut, cherry, poplar. Prices run $3 to $20+ per board foot depending on species and grade. Buy FAS (Firsts and Seconds) grade for furniture; No. 1 Common for smaller parts. Ask to hand-select boards before purchase.

For outdoor projects (decks, fences, pergolas): use pressure-treated lumber rated UC3B for above-ground, UC4A or UC4B for ground contact. Cedar and redwood are naturally rot-resistant alternatives without treatment chemicals; cost more but are easier to work with and take stain better.

Frequently Asked Questions