Lumber Calculator
Calculate board feet from lumber dimensions — thickness, width, length, and quantity — for pricing and ordering.
How to use this lumber calculator
- 1Enter nominal lumber dimensions (2×6 = thickness 2, width 6), not actual finished dimensions.
- 2Enter length in feet.
- 3Enter the number of pieces you need.
- 4Board feet is used for pricing hardwood; softwood framing lumber is typically priced by the linear foot.
- 5For hardwood purchases, confirm whether the supplier prices by nominal or actual dimensions.
How it's calculated
Board feet = (T × W × L) ÷ 12, where T and W are in inches and L is in feet. Use nominal dimensions for pricing.
About the Lumber Calculator
Board feet calculation is fundamental to hardwood lumber purchasing — whether you are building furniture, custom cabinetry, flooring, or any project requiring hardwood species. Unlike softwood framing lumber sold by the stick at fixed prices, hardwood lumber pricing by board foot scales with the actual volume of wood, making it possible to purchase exactly what you need from boards of varying width, thickness, and length.
Hardwood lumber is typically sold in random widths (boards as they come from the log, varying from 4 to 16+ inches wide) and random lengths (6 to 16+ feet). This purchasing model requires more planning than buying dimensional softwood but allows selection of specific grain patterns, wood figure, and color variation. Working with random widths and lengths also requires calculating yield — how many usable pieces of required dimensions can be cut from each board, accounting for defects and waste.
The nominal versus actual dimension distinction matters significantly when planning joints and assemblies. A cabinet built with 3/4-inch plywood combined with 1×4 boards that actually measure 0.75 × 3.5 inches requires careful dimension planning to ensure all components work together. Professional woodworkers and cabinetmakers measure actual dimensions of all materials before designing joinery, rather than relying on nominal labels.
For sustainable sourcing, FSC-certified (Forest Stewardship Council) lumber ensures that the wood was harvested from responsibly managed forests. Reclaimed lumber — salvaged from demolished buildings, barns, and industrial structures — offers both environmental benefits and unique aesthetic qualities from old-growth wood species and weathered character that new lumber cannot replicate. Many woodworkers find reclaimed material more interesting and beautiful than new wood, particularly for furniture and feature applications.
Frequently asked questions
What is a board foot and why does it matter?
A board foot is a unit of volume used for measuring lumber: one board foot equals 1 inch thick × 12 inches wide × 12 inches long (144 cubic inches). It standardizes pricing across different lumber dimensions — instead of specifying a price for each width and thickness combination, hardwood dealers price by board foot, allowing easy comparison. Softwood framing lumber (2×4, 2×6, etc.) is typically priced by the linear foot or by the piece, not by board foot. Hardwood lumber — oak, walnut, maple, cherry — is almost always sold and priced by the board foot.
Why does a 2×4 not actually measure 2 inches by 4 inches?
Lumber nominal dimensions (the label: 2×4, 2×6, etc.) are the rough-cut dimensions before kiln drying and surfacing. The drying and planing process removes material, producing smaller actual dimensions. Common nominal vs actual: 2×4 = actual 1.5×3.5 inches, 2×6 = 1.5×5.5 inches, 2×8 = 1.5×7.25 inches, 1×6 = 0.75×5.5 inches. Use nominal dimensions when calculating board feet for pricing purposes (since the board foot formula was developed based on nominal sizes), but use actual dimensions when calculating structural spans, clearances, or precise joinery. Hardwood lumber is often sold by actual dimensions after surfacing — always confirm which convention applies when purchasing.
What is the difference between dimensional lumber and hardwood lumber?
Dimensional lumber (also called construction lumber or framing lumber) is typically softwood (pine, fir, spruce) sold in standard nominal sizes (2×4, 2×6, etc.) primarily for structural framing applications. It is graded for structural strength (Select Structural, No. 1, No. 2, etc.) and is priced by linear foot or piece. Hardwood lumber (oak, maple, walnut, cherry, poplar) is typically sold rough-sawn or surfaced, in random widths and lengths, priced by the board foot. Hardwood is used for furniture, cabinets, flooring, and decorative woodworking. Hardwood grades focus on clear (knot-free) percentage: FAS (Firsts and Seconds) is the highest grade with largest clear cuttings; Select and No. 1 Common have progressively more character marks.