How to use the log volume calculator
- Measure both end diameters in centimeters, consistently inside or outside bark.
- Enter log length in meters and quantity only for logs with matching dimensions.
- Use gross volume for geometric comparison. Use a specified log rule if a buyer requires a sawlog tally.
The formula
Smalian volume (m³) = π × (small diameter² + large diameter²) ÷ 80,000 × length (m)
Worked example
A 4 m log with end diameters of 30 and 40 cm has an estimated volume of 0.393 m³ before deductions for defects or processing.
Before you measure and cut
Smalian’s method averages end areas. Strong butt swell, sweep, and irregular cross sections can reduce accuracy.
For a cylinder, enter the same diameter at both ends. Bark, saw kerf, slabs, and defects are not automatically deducted.
Frequently asked questions
Is this a Doyle or Scribner log rule?
No. Those estimate a sawn-lumber tally using different conventions. This calculator reports round-log geometric volume.
Should I measure over bark?
Use the convention required for your purpose and keep it consistent. Inside-bark measurements exclude bark volume.