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Log measurement

Measuring log volume: Huber and Smalian

Two common formulas turn a log's diameter and length into solid volume. They differ in which diameter they use.

This article was drafted with AI assistance and has not yet been reviewed by an expert. Check important figures against a standard or your contract before relying on them.

Why volume is calculated

A round log is bought and sold by volume. Because a log is not a perfect cylinder, the result depends on the formula and on where the diameter is measured.

Huber

Huber uses the diameter at the middle of the log:

V = π/4 × d² × L

With a middle diameter of 30 cm and a length of 4 m, the volume is about 0.283 m³. Use consistent units: diameter in metres inside the formula (0.30 m), length in metres.

Smalian

Smalian averages the cross-section areas of both ends:

V = π/8 × (d₁² + d₂²) × L

For a log with a strongly tapering shape, Smalian tends to give a larger value than Huber, because the average of two end areas is larger than the area at the middle diameter of a cone-like log.

What to watch for

Diameters are normally taken under bark. Agree with the buyer whether bark is deducted.
Many markets sort and pay by top diameter and length classes, not by a formula. The contract rule always wins.
Defects such as sweep, rot or forks are not reflected in these formulas.

You can try both formulas with the Log volume calculator.

Sources

Derived from definitions and the formulas used in the portal tools; no external source is cited.

Last updated 2026-10-23