Wood Weight Calculator
Calculate the weight of a wood board or timber from its dimensions and species density. Use it for lumber shipping cost estimation, structural load calculations, and workshop material handling planning.
Last updated: May 2026
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About this calculator
The formula is: weight (lbs) = (length × width × thickness × density) / 1728, where length, width, and thickness are in inches and density is in lbs/ft³. The /1728 converts cubic inches to cubic feet (12³ = 1728), since density is per cubic foot. Edge cases: zero values produce zero output; negative values are nonsensical. Wood density varies significantly by species and moisture content. Reference densities at 12% moisture content (kiln-dried furniture-grade): softwoods — Eastern white pine 25 lbs/ft³, Ponderosa pine 28, Western red cedar 23, Douglas fir 33, Southern yellow pine 35. Hardwoods — basswood 26 lbs/ft³, poplar 28, soft maple 33, cherry 35, walnut 38, white oak 47, hard maple 44, ash 41, birch 43, mahogany 35–40, teak 41, ebony 70+. Tropical hardwoods (ipe, lignum vitae) can exceed 75 lbs/ft³. Density changes with moisture: green (freshly cut) wood weighs 1.5–2× the kiln-dried weight; air-dried (12–18% MC) is intermediate. For accurate calculation, use density values matched to your wood's current moisture state. A typical 8-foot 2×4 (1.5" × 3.5" × 96") of Southern yellow pine at 35 lbs/ft³ weighs about 10.2 lbs; a 4×8 sheet of 3/4" plywood (~28 lbs/ft³ depending on construction) weighs about 56 lbs. For board feet weight (1 BF = 144 cubic inches), density / 12 gives lbs/BF — useful for lumberyard ordering and truck loading. Note that "nominal" lumber dimensions (2×4, 2×6) differ from actual (1.5×3.5, 1.5×5.5) — always use actual measured dimensions for weight calculations.
How to use
Example 1 — Single 8-foot oak board. White oak board: 96" long × 8" wide × 1" thick at 47 lbs/ft³ density. Enter length 96, width 8, thickness 1, density 47. Result: (96 × 8 × 1 × 47) / 1728 = 36,096 / 1728 ≈ 20.9 lbs. ✓ A standard piece of premium hardwood — manageable to carry but worth handling carefully for finish surfaces. At ~$8–12 per board foot for premium oak, this 5.3 BF piece costs $40–65 retail. Example 2 — Stack of construction lumber. 50 pieces of 2×4 × 8 ft Southern yellow pine (actual dimensions 1.5" × 3.5" × 96") at 35 lbs/ft³. Per piece: (96 × 3.5 × 1.5 × 35) / 1728 = 17,640/1728 ≈ 10.2 lbs. Stack: 50 × 10.2 = 510 lbs. ✓ A typical residential framing bundle. Plan transport accordingly — a half-ton pickup truck handles this load fine in the bed; a sedan would be overloaded. For larger lumber deliveries, request a forklift offload or have a tractor/skid-steer available.
Frequently asked questions
What density should I use for my specific wood?
Reference values from the USDA Forest Products Laboratory Wood Handbook are the standard. Common species (lbs/ft³ at 12% moisture): white pine 25, hemlock 28, Douglas fir 33, yellow pine 35, redwood 28, Western red cedar 23, basswood 26, poplar 28, soft maple 33, hard maple 44, cherry 35, walnut 38, white oak 47, red oak 44, ash 41, birch 43, hickory 51, mahogany 35–40 (varies by species), teak 41, ebony 70+. Tropical hardwoods range widely: ipe 69, jatoba 56, purpleheart 56, padauk 47, bubinga 53. Plywood and engineered lumber: typical plywood 28–32 (depending on core species and adhesive); OSB 35; MDF 45–48; particle board 40–50; melamine-faced board ~50. Live-edge and freshly milled wood (green): typically 1.5–2× the kiln-dried density. Pressure-treated lumber is 5–15% heavier than untreated equivalent due to chemical retention. For precision applications, weigh a known sample and back-calculate density rather than trust generic tables — there is significant variation within species depending on growth location, density of growth rings, and processing.
How does moisture content affect wood weight?
Substantially. Freshly cut "green" wood typically holds 30–200% moisture content (MC) by weight — meaning the water in the wood weighs 0.3–2× as much as the dry wood substance. Kiln-dried furniture lumber is typically 6–10% MC; air-dried is 12–18% MC; "structural" lumber for framing is typically 15–19% MC (the "S-DRY" stamp confirms <19%). The same board of red oak at green vs kiln-dried MC: green ~70 lbs/ft³ at ~60% MC; kiln-dried ~44 lbs/ft³ at 8% MC — a 60% weight difference. For shipping and load calculations, use the actual MC condition of the wood you're handling. Standard reference tables give density at 12% MC (most useful for furniture-grade lumber); adjust upward by ~0.5–1% of weight per 1% MC increase. For green or freshly milled lumber stocks, weight planning at delivery is critical because trucks rated for kiln-dried loads can be overloaded by 30–50% when carrying green wood. The Wood Handbook provides correction factors for any MC condition.
How do I calculate weight in metric units?
Use metric inputs: weight (kg) = length (m) × width (m) × thickness (m) × density (kg/m³). Common conversions: 1 lb/ft³ = 16.018 kg/m³; multiply lbs/ft³ table values by 16.018 to get kg/m³. So white oak at 47 lbs/ft³ = 753 kg/m³; Douglas fir at 33 lbs/ft³ = 529 kg/m³. For a 2-meter × 0.2m × 0.025m white oak board: 2 × 0.2 × 0.025 × 753 = 7.53 kg. The metric formulation is cleaner because cubic meters is a natural unit; no unit conversion factor like /1728 is needed. European and international wood references typically use kg/m³ directly. For mixed-unit work, convert dimensions to consistent units first (all inches with lbs/ft³, or all meters with kg/m³). Janka hardness (hardness rating for wood species) is independent of density and provides a different ranking — dense woods are typically harder, but exceptions exist (balsa is very light but somewhat harder than expected; some tropical hardwoods are very dense but moderately hard).
What are the most common wood weight calculation mistakes?
The biggest is confusing nominal and actual lumber dimensions; a "2×4" is 1.5" × 3.5", not 2" × 4". Always use actual measured dimensions. The second is using the wrong density for the wood's actual moisture state — kiln-dried density for green lumber under-estimates by 30–60%. The third is averaging "hardwood" or "softwood" density across species; the variation within categories is huge (basswood 26 vs hickory 51 lbs/ft³). Look up the specific species. The fourth is forgetting to subtract removed material — a slab with a large hole or rabbet weighs less than the bounding rectangle suggests. The fifth is using table-published density without verifying for treated, engineered, or unusual products; pressure-treated, fire-retardant-treated, and resin-impregnated lumber can be 10–30% heavier than the same untreated species. The sixth is not accounting for finish weight — paint, polyurethane, oil finishes add a small but measurable weight (typically 0.5–2 lbs per gallon applied per 400–500 sq ft of surface). The seventh is using density values from non-authoritative sources; some hobby websites publish wrong numbers. Use USDA FPL Wood Handbook or major lumber industry references. The eighth is forgetting that veneer-cored plywood is significantly lighter than MDF-cored or particleboard-cored sheet goods; specify which type for accurate weight. The ninth is failing to account for stack settlement and binding hardware (banding, pallets) when weighing bulk lumber.
When should I not use this calculator?
Skip it for engineered structural members where the manufacturer publishes precise weight specifications (LVL, glulam, parallam, I-joists, trusses) — use those rather than generic density math. It is the wrong tool for hollow construction (cabinets, boxes, furniture) where the assembly weighs much less than the gross dimensions suggest; estimate by component or by similar finished product weight. Do not use it for green lumber or undried timber without adjusting density for actual moisture content; use moisture-corrected density values. For tropical exotic species not in standard tables, weigh a known sample and back-calculate density rather than guess. For composite materials (Trex decking, Azek, ipe-look composites), use manufacturer-published weight specifications — these differ from traditional wood density. For round logs and irregularly shaped pieces (slab tables, live-edge lumber, sculpted blanks), use volume calculation matching the actual shape rather than length × width × thickness rectangle. For very thin veneers and laminates where surface treatments add significant mass, factor in finish weight. And for design load calculations on critical structural members (rafters, beams, columns), use engineered load tables from structural design references rather than weight-from-density math; structural calculations need both weight and material properties together.