Log Weight Calculator (green weight by species, diameter & length)

Understanding the log weight calculator — concept and principle

This calculator estimates the weight of a freshly cut or partly dried log from its species, its two end diameters, its length and its moisture content. Woodcutters, arborists and hobby sawyers use it to plan lifting, loading a trailer or choosing equipment.

Volume × green density: with the default inputs the result is ≈ 220 kg (≈ 485 lb, 91 kg is water).

How it is calculated

Volume (frustum of a cone, without bark): V = π × L ÷ 12 × (d₁² + d₁ × d₂ + d₂²), diameters and length in metres.
Dry wood per m³ = basic specific gravity G × 1,000 kg.
Weight = V × G × 1,000 × (1 + MC ÷ 100), where MC is water as a percentage of the dry wood.
With MC set to 0, the species' average green moisture content is used (white oak 71%).
Water per log = dry wood × MC ÷ 100.

The principle

A log tapers, so treating it as a cylinder would overstate its volume; the frustum formula uses both end diameters. Basic specific gravity is the oven-dry mass divided by the green volume, which tells you how much actual wood substance a cubic metre holds. Freshly cut wood also holds a lot of water, often more than half its dry mass, and that water can make up a large share of the weight. Moisture content is therefore measured on a dry basis, and the total weight is dry wood times (1 + MC). The species values come from the USDA Wood Handbook as compiled by Penn State Extension.

Worked example

Default inputs: white oak (G = 0.60), small end 30 cm, large end 36 cm, length 2.5 m, freshly cut (MC 71%), 1 log.

Volume = π × 2.5 ÷ 12 × (0.09 + 0.108 + 0.1296) = 0.214 m³.
Density = 0.60 × 1,000 × 1.71 = 1,026 kg/m³.
Weight = 0.2144 × 1,026 = 220 kg (485 lb).
Dry wood = 0.2144 × 600 = 129 kg; water = 128.6 × 0.71 = 91 kg.

Each point is the calculator re-run with only “Log length (m)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Log length (m)	Weight of all logs (kg)
0.625	55
1.25	110
1.88	165
2.5	220
3.12	275
3.75	330
5	440

How to read the result

Green hardwood logs are often heavier than people expect, and a log of this size is well beyond a safe one-person lift. As wood dries, the weight falls towards the dry-wood figure, though air-dried wood still holds some moisture. Bark, heartwood and sapwood differences, and knots and rot, all change the real weight.

Common mistakes

Using the same diameter at both ends, which overstates tapered logs.
Measuring diameters over the bark.
Treating moisture content as a share of the total weight instead of the dry weight.
Picking the wrong species, since densities differ a lot.

Keep in mind: This is an estimate. Use proper lifting equipment and techniques, and never rely on an estimate near the safe working load of a winch, crane or trailer.

Frequently asked questions

How much does a white oak log weigh?

A freshly cut white oak log 2.5 m long with 30 and 36 cm ends weighs about 220 kg.

How much does green wood weigh per cubic metre?

It depends on species; freshly cut white oak is about 1,026 kg/m³.

Why use moisture content on a dry basis?

It is the standard for wood and makes the weight simply dry wood × (1 + MC).

Sources: Penn State Extension, "Calculating the Green Weight of Wood Species" (2025) · USDA Forest Products Laboratory, Wood Handbook (2010), Tables 4-1 and 5-3 to 5-5

Checked 9 Nov 2026. Penn State Extension, “Calculating the Green Weight of Wood Species” (updated 2025): green weight = oven-dry mass × (1 + MC), with basic specific gravity and average green moisture content from USDA Forest Products Laboratory, Wood Handbook (2010), Tables 4-1 and 5-3 to 5-5.

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