The Smalian's Formula - Imperial Multi-Log Calculator estimates the volume of multiple logs using imperial units: length in feet and diameters in inches. Based on Smalian's method for calculating the volume of a truncated cylinder, this calculator adds up each log's volume and returns a running total in cubic feet, with optional export to CSV and copy-to-clipboard functionality.
Click Add Log to enter multiple logs. Input the length and the two diameters of each log. Click Calculate to view board feet per log and total. Use Copy History or Download CSV to save your results.
Looking for metric units? Switch to the Smalian's Formula - Multi-Log Calculator - Metric.
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Total Volume: 0 ft3 / 0 m3
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Smalian's formula (imperial) for a single log's volume (in cubic feet) is given by:
\[ V \;=\; \frac{\pi}{1152}\,\bigl(D_{s}^{2} + D_{l}^{2}\bigr)\,L \]
where:
This formula yields volume \(V\) in cubic feet (ft³). The factor \(\tfrac{\pi}{1152}\) comes from averaging cross-sectional areas and converting square inches to square feet.
Suppose we have a single log with these measurements:
Compute step by step:
Step 1: Square the diameters (in inches):
\(D_{s}^{2} = 10^{2} = 100,\quad D_{l}^{2} = 12^{2} = 144.\)
Step 2: Sum the squared diameters:
\(D_{s}^{2} + D_{l}^{2} = 100 + 144 = 244.\)
Step 3: Multiply by length \(L = 8\) ft:
\(\bigl(D_{s}^{2} + D_{l}^{2}\bigr)\,L = 244 \times 8 = 1952.\)
Step 4: Multiply by \(\tfrac{\pi}{1152}\):
\[ V = \frac{\pi}{1152} \times 1952 = \pi \times \frac{1952}{1152} = \pi \times 1.6944\ldots \approx 1.6944 \times 3.1416 = 5.3228\ldots \]
Numerically, \(1.6944 \times \pi \approx 5.323\).
Step 5: Final volume (rounded to three decimals):
\[ V \approx 5.323 \;\text{ft³}. \]
Summary of sample result:
This tool is ideal for log scalers and forestry professionals working in imperial units.