Nominal Thickness vs Surfaced Actual ThicknessQuarters of Inch (4/4 to 16/4) | Caliper Rough Dimension
Nominal thickness represents the rough-sawn dimension before kiln drying and surface planing. Under National Hardwood Lumber Association (NHLA) grading standards, surfaced hardwood lumber (surfaced two sides S2S or surfaced four sides S4S) is commercially billed at its original rough nominal thickness—for example, 13/16-inch planed white oak is billed as 4/4 (1.00 inch), and 1-3/4-inch planed maple is billed as 8/4 (2.00 inches). Softwood structural framing lumber follows the American Softwood Lumber Standard (PS 20), where 2-by stock is dressed to 1.50 inches actual thickness but billed at 2.00 inches nominal.
Default: 4/4 (1.00 in nominal / 13/16 in surfaced)
Nominal Width vs Surfaced Actual WidthNominal Trade Inches | Dressed Face Dimension
Nominal width is the standardized green sawmill reference size prior to drying shrinkage and planar surfacing. Under American Softwood Lumber Standard PS 20 guidelines, dimensional lumber undergoes calibrated reduction: 2x4 lumber finishes to 3.50 inches actual; 2x6 finishes to 5.50 inches; 2x8 finishes to 7.25 inches; 2x10 finishes to 9.25 inches; and 2x12 finishes to 11.25 inches. Hardwood boards are sold in random widths measured across the face to the nearest quarter or half inch at the narrowest point.
Default: 6.0 in nominal (5.5 in actual for 2x6)
Board LengthLongitudinal Linear Run (Feet | Inches | Meters)
The physical dimension running parallel with the wood grain from end to end. Softwood framing lumber is harvested and milled in standardized even-foot lengths (8, 10, 12, 14, and 16 feet), whereas premium architectural hardwoods are tallied in random lengths measured to the nearest foot, with fractions typically rounded down under commercial lumber tally grading conventions.
Default: 8.0 feet
Foot Board Measure (FBM / Board Foot)Lumber Volume Constant (144 cu in | 1/12 cu ft)
The standardized unit of volumetric lumber measurement across the North American timber industry, abbreviated as BF or FBM. One board foot represents the solid wood volume of a board 1 inch thick by 12 inches wide by 12 inches long (144 cubic inches, equivalent to 1/12 of a cubic foot or 0.0023597 cubic meters). In wholesale timber trading, volume is routinely quoted in thousands of board feet, denoted as MBF (1 MBF = 1,000 BF).
Default: 1 BF = (T × W × L) / 12
Waste & Defect AllowanceMaterial Contingency Margin (0% to 50%)
The supplemental volumetric percentage added to net finished cutting lists to account for natural wood defects, saw kerf loss, planar snipe, end-checking cracks, cup, twist, and sapwood edge removal. Industry standard allowances: Pre-surfaced dimensional S4S softwood requires 10%; Firsts and Seconds (FAS) rough hardwood requires 15% to 20%; #1 Common hardwood requires 20% to 25%; and highly figured timbers, live-edge slabs, or sapwood-rich species like Black Walnut require 25% to 35%.
Default: 15% (Standard FAS Hardwood)
Price per Board Foot ($/BF)Commercial Unit Volume Rate ($/BF | €/m³)
The standard wholesale and retail billing unit rate per board foot. Hardwood lumber pricing scales based on wood species scarcity, lumber grade (FAS, Select, #1 Common), rough thickness (thicker stock like 8/4 carries a 20% to 40% kiln-drying premium over 4/4 due to extended drying schedules), and regional harvest availability.
Default: $8.50 / BF (White Oak FAS)
Wood Species Density & Moisture ContentVolumetric Mass Rating (lb per BF | kg per m³)
The wood mass per unit board foot determined by species specific gravity and moisture content (MC). Standard interior cabinet hardwoods are kiln-dried to 6% to 8% equilibrium moisture content, weighing between 3.2 and 4.2 pounds per board foot (e.g., kiln-dried Cherry at 2.9 lb/BF, Hard Maple at 3.9 lb/BF, White Oak at 4.0 lb/BF). Freshly cut green timber contains 30% to over 100% moisture content, increasing weight by 50% to 80% and critically impacting vehicle hauling payload limits.
Default: 4.00 lb/BF (White Oak KD)
Surface Area vs Board Foot EquivalenceTwo-Dimensional Planar Area (Sq Ft | m²)
The geometric relationship between surface coverage and volumetric board measure. For 4/4 lumber (1.00 inch nominal thickness), exactly 1 square foot of surface area equals 1 board foot. For 8/4 stock (2.00 inches nominal thickness), 1 square foot equals 2 board feet. Conversely, when purchasing thin stock such as 1/2-inch or 3/4-inch boards, commercial lumberyards bill at the full 1.00-inch (4/4) rate per square foot unless explicitly sold under specialized surface measure (SM) rules.
Default: 1 BF = 1 Sq Ft at 4/4 Thickness
