Lumber Calculator
Planning a deck, fence, or framing job starts with knowing exactly how much wood to order. This lumber calculator converts your cut list — nominal size, length, and quantity — into total board feet, linear feet, estimated cost, and a weight estimate for delivery planning. It uses actual dressed dimensions (a 2×4 is really 1.5 × 3.5 in), so your takeoff matches what the yard sells.
The name on the label; actual milled dimensions are smaller.
Number of identical pieces.
Optional — leave 0 to skip the cost estimate.
Used only for the weight estimate.
Total board feet
35bf
- Total pieces
- 10
- Total linear feet
- 80ft
- Board feet per piece
- 3.5bf
- Estimated material costEnter a price per piece above to estimate cost.
- 0
- Estimated weightRule-of-thumb density for pine/fir; varies with moisture.
- 90.4lb
How it was calculated
- 1.5 in × 3.5 in × 8 ft ÷ 12 = 3.500 board feet per piece
- 3.500 bf × 10 pieces = 35.00 board feet total
- Weight: 0.2917 ft³/piece × 31 lb/ft³ × 10 = 90.4 lb
How it works
A board foot is a volume measure: one board foot equals 144 cubic inches — the volume of a board 1 inch thick, 12 inches wide, and 12 inches long. It puts every lumber size on one comparable scale.
Lumber is sold by nominal size but milled smaller. This calculator maps each nominal size to its actual dressed dimensions: 2×4 → 1.5 × 3.5 in, 2×6 → 1.5 × 5.5 in, 2×8 → 1.5 × 7.25 in, 2×10 → 1.5 × 9.25 in, 4×4 → 3.5 × 3.5 in, and 1×6 → 0.75 × 5.5 in.
Board feet per piece = actual thickness (in) × actual width (in) × length (ft) ÷ 12. Multiplying by quantity gives total board feet; multiplying length by quantity gives total linear feet.
Weight is estimated from volume: piece volume in cubic feet × a rule-of-thumb species density (about 31 lb/ft³ for pine/fir, 45 lb/ft³ for oak), times quantity. Cost is simply price per piece × quantity.
Worked examples
Deck frame takeoff
You need 24 pieces of 2×8, each 12 ft long. Each piece holds 1.5 × 7.25 × 12 ÷ 12 = 10.875 board feet, so 24 pieces = 261 board feet and 288 linear feet. At $11.40 per piece the material costs $273.60, and at pine density the load weighs about 674 lb — handy for delivery planning.
Fence pickets
A fence needs 120 pickets of 1×6 × 6 ft. Each picket is 0.75 × 5.5 × 6 ÷ 12 = 2.0625 board feet, for 247.5 board feet total and 720 linear feet. At $3.20 per picket the material estimate is $384.00 before tax.
How to measure
- Work from a cut list, not a guess: group boards by identical size and length before you start.
- Measure length in feet — yard stock comes in 8, 10, 12, 14, and 16 ft lengths.
- Count every piece, including blocking, bracing, and trim; small pieces add up fast.
- Add 10–15% extra after the calculator gives the net total, for cuts, defects, and mistakes.
- For delivery, note the weight estimate and check your vehicle or trailer rating before loading.
Assumptions & limitations
Planning estimate
- Nominal sizes map to actual dressed dimensions per standard US softwood milling (e.g., 2×4 → 1.5 × 3.5 in); imported or rough-sawn stock can differ.
- Species densities (pine/fir ≈ 31 lb/ft³, oak ≈ 45 lb/ft³) are a rule of thumb for air-dried stock — actual weight varies with moisture content.
- No waste factor is included; add 10–15% for cutting and defects.
- Cost excludes sales tax, delivery fees, fasteners, and hardware.
- Board feet measure volume, not strength — span and load decisions need span tables or an engineer.
Frequently asked questions
Nominal sizes date back to rough-sawn dimensions. Modern lumber is planed smooth (dressed) after sawing, which removes about half an inch. A 2×4 therefore finishes at 1.5 × 3.5 inches. This calculator uses the actual dimensions so the volume math is correct.
Linear feet tell you how many feet of board to buy — what the yard charges by the piece. Board feet measure total wood volume, which is how hardwood is priced and how you compare the true material content of different sizes. This calculator gives you both.
Add 10–15% over the net takeoff for cutting waste, knots, warping, and mistakes. Complex cuts like stair stringers or angled deck boards deserve the higher end. The calculator shows net quantities, so apply the waste factor yourself.
It is a planning estimate. Density varies with species, moisture content, and treatment — pressure-treated lumber can weigh 20–30% more than the same size dry. Use the estimate for delivery planning, not for structural loading.
The Board Foot Calculator converts a single board to board feet — a unit conversion. The Lumber Calculator is a project takeoff: it takes a full cut list (size, length, quantity, price) and returns total board feet, cost, and weight.