Timber Weight Calculator — Estimate Wood Weight by Species

Kiln-dried European oak weighs approximately 720 kg/m³. Air-dried oak at 20% moisture content weighs around 750 kg/m³ (density rises by roughly 0.5% per 1% moisture below the fibre saturation point, as the timber gains mass but also swells), 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.

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.

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.

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.