The Smalian's Formula - Imperial Log Volume Calculator estimates log volume using imperial units: length in feet and diameters in inches. This calculator applies Smalian's geometric formula for approximating log volume when both end diameters are known and uses the standard conversion to cubic meters for metric reference.
Smalian's formula is named after the German forestry scientist Heinrich Christian Smalian (1800-1875), who is credited with developing one of the earliest mathematical methods for estimating the volume of a log based on its end diameters and length.
\[ V_{ft^3} = 0.005454 \cdot \left( D_s^2 + D_l^2 \right) \cdot \frac{L}{2} \]
\[ V_{m^3} = V_{ft^3} \cdot 0.0283168 \]
Small End = 12 in, Large End = 18 in, Length = 20 ft: \[ \begin{align*} V_{ft^3} &= 0.005454 \cdot (12^2 + 18^2) \cdot \frac{20}{2} \\\\ &= 0.005454 \cdot (144 + 324) \cdot 10 \\\\ &= 0.005454 \cdot 468 \cdot 10 \\\\ &= 25.54 \, \text{ft}^3 \end{align*} \] \[ V_{m^3} = 25.54 \cdot 0.0283168 = 0.723 \, \text{m}^3 \]
This tool is ideal for log scalers and forestry professionals working in imperial units.