Roy Log Rule Board Foot Calculator

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Formula

The formula used to calculate the volume is:

\[ \text{Board Feet} = \frac{(D - 1)^2 \times L}{20} \]

Definition

The Roy Log Rule, with results in board feet, was used by mills in Quebec, Canada. The results from this rule are fairly accurate for 14' and 16' logs but over scales slightly on the high end for smaller sized logs.

Steps to calculate the volume:

Measure the diameter on the small end of the log in inches.
Enter the length of the log in feet.
The formula calculates the volume in board feet, cubic feet, and cubic meters.

Example Calculation

Let's assume the following values:

Diameter = 20 inches
Length = 16 feet

Using the formula:

\[ \text{Board Feet} = \frac{(20 - 1)^2 \times 16}{20} = 288 \]

Conversion Chart

Diameter (inches)	Length (feet)	Volume
6	16	20.0
8	16	39.2
10	16	64.8
12	16	96.8
14	16	135.2
16	16	180.0
18	16	231.2
20	16	288.8
22	16	352.8
24	16	423.2
26	16	500.0
28	16	583.2
30	16	672.8
32	16	768.8
34	16	871.2
36	16	980.0