How much does oak weigh per cubic metre?

Kiln-dried European oak weighs approximately 720 kg/m³. Air-dried oak at 20% moisture content weighs around 780 kg/m³, and green (freshly felled) oak can weigh over 1,000 kg/m³. American white oak is slightly lighter at around 680 kg/m³ kiln dried.

Why does moisture content affect timber weight?

Wood absorbs and releases water depending on conditions. Green (freshly felled) timber can contain 60% or more moisture by weight — water filling the cell cavities and saturating the cell walls. As it dries, the water evaporates and the weight decreases significantly. Kiln-dried timber at 12% MC is the standard reference point for density.

How do I estimate the weight of a timber beam?

Multiply the length, width, and depth in metres to get volume in m³, then multiply by the species density in kg/m³. For example, a 3m x 150mm x 200mm oak beam: 3 x 0.15 x 0.2 = 0.09 m³. At 720 kg/m³ (kiln dried), it weighs approximately 64.8 kg.

What is specific gravity in timber?

Specific gravity (SG) is the ratio of wood density to water density (1000 kg/m³). An SG of 0.72 means the wood is 720 kg/m³. Most commonly used hardwoods have an SG between 0.5 and 0.8. Woods with SG above 1.0 (like lignum vitae) sink in water.

WoodCalcs

Timber Weight Calculator — Estimate Wood Weight by Species

Estimate timber weight by species, dimensions, quantity, and moisture content. Supports pine, oak, ash, walnut, maple, cherry, mahogany, and custom densities.

Species

Moisture Content

Select the moisture content for your calculation

Length

Longest dimension of the area

Width

Shortest dimension of the area

Thickness

Material thickness

Quantity

Number of items needed

How We Calculate This

This calculator estimates timber weight by multiplying the volume of each piece (from dimensions) by the density of the selected species, adjusted for moisture content.

Formula

Weight = Volume (m³) x Density at MC (kg/m³)

Densities at 12% MC (kg/m³)

Pine: 510
Cherry: 580
Mahogany: 540
Walnut: 640
Ash: 670
Maple: 700
Oak: 720

Moisture adjustments

Kiln dried (12%): base density (x1.0)
Air dried (20%): +8% (x1.08)
Green (~60%): +45% (x1.45)

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Always verify measurements and material quantities before cutting or purchasing.