Lumber and Wood Species Properties
Look up density, Janka hardness, modulus of elasticity, and modulus of rupture for 18 wood species.
Calculate board weight from dimensions.
Wood is one of the most variable structural materials in common use — the same species can differ by 20–30% in strength properties depending on moisture content, growth rate, and grain orientation. Understanding the key properties helps you choose the right species for each application.
Janka Hardness measures the force (in pounds-force, lbf) required to embed a 0.444-inch (11.28 mm) steel ball to half its diameter into the wood. It is the most widely used measure of wear resistance and hardness for flooring and woodworking applications. Higher Janka = harder, more scratch-resistant, and usually harder to work with hand tools.
| Category | Janka Range | Example |
|---|---|---|
| Very soft | < 500 lbf | Western Red Cedar (350), Ponderosa Pine (460) |
| Soft-moderate | 500–900 lbf | Douglas Fir (660), SPF (500) |
| Moderately hard | 900–1200 lbf | Black Walnut (1010), Red Oak (1290) |
| Hard | 1200–1600 lbf | Hard Maple (1450), White Oak (1360) |
| Very hard | > 1600 lbf | Hickory (1820), Brazilian Cherry (~2820) |
Modulus of Elasticity (MOE) — measured in million psi (Mpsi) — is the measure of stiffness. A higher MOE means less deflection (sag) under load. This is critical for structural beams, floor joists, and shelving. Douglas Fir (MOE = 1.95 Mpsi) deflects less than Ponderosa Pine (1.29 Mpsi) under the same load, which is why Fir dominates structural framing.
Modulus of Rupture (MOR) — measured in psi — is the bending strength. It tells you how much load a beam can carry before it breaks. A 2×10 Southern Yellow Pine joist can carry significantly more load than a 2×10 SPF joist because SYP has MOR = 14,500 psi vs SPF’s 10,500 psi.
Density and Weight Estimation: Weight = (Width_in × Thickness_in × Length_ft × 12) / 1728 × Density_lb_per_ft³
All density values on this page are at approximately 12% moisture content (MC) — the equilibrium moisture content for wood stored indoors in temperate climates. Green (freshly cut) wood can be 50–100% heavier due to water content.
Worked Example — 2×6 Douglas Fir, 8 feet: Actual dimensions: 1.5" × 5.5" (nominal 2×6) Volume = 1.5 × 5.5 × 96 (inches) = 792 in³ = 0.458 ft³ Weight = 0.458 × 30 lb/ft³ = 13.8 lbs
Hardwood vs Softwood — Botanical Definition: Despite the names, hardwoods and softwoods are classified by seed type, not actual hardness. Hardwoods (angiosperms) have enclosed seeds — oak, maple, walnut. Softwoods (gymnosperms) have naked seeds like pine cones — pine, fir, spruce. Balsa wood is technically a hardwood yet is one of the softest woods on earth (Janka ≈ 67 lbf).
Moisture Content Warning: Structural lumber must be dried to 19% MC or less (usually kiln-dried to 15%) before installation. Wet wood shrinks as it dries, causing warping, cupping, and nail pops in finished construction.