What is the Scribner Decimal Rule?

The Scribner Decimal Rule is a log scaling method used to estimate board feet based on a log's length and small-end diameter. It approximates the original Scribner log rule tables with a formula.

What inputs does this calculator require?

You need to enter the log length in feet and the diameter inside bark (DIB) at the small end in inches.

Does this calculator show a running total?

Yes, each calculation adds to a running total of board feet that updates automatically as you add logs.

Can I copy or export my calculations?

Yes, the full history of log entries and totals can be copied to your clipboard or downloaded as a CSV file.

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Scribner Decimal Log Rule Calculator

This calculator uses the Scribner Decimal C Rule to estimate the board feet of lumber contained in a log. The formula is based on empirical approximations that closely match the Scribner table values and is commonly used in the forestry and logging industry.

The Scribner Log Rule was developed by J.M. Scribner, a New York-based timber cruiser and surveyor, in 1846. It was one of the first standardized methods in the United States for estimating the board foot volume of logs before milling.

Scribner created this rule by drawing diagrams of boards that could be sawn from logs of various diameters and lengths. His rule assumed a kerf (saw blade width) of 1/4 inch and a log taper based on a relatively short log length (typically 16 feet).

Doyle Log Rule Calculator - Estimate board feet using the Doyle Rule for rough lumber yield, most common in the eastern U.S.
International 1/4-Inch Rule Calculator - Calculate board feet using a more consistent scaling rule used in the western U.S. and Canada.
Log Weight Estimator - Estimate the weight of logs using tree species and dimensions for planning transport or lifting.

Scribner Decimal Rule Calculator

Length of Log in Feet
ft

DIB Log Small End in Inches
inch

Diameter Measured Inside Bark = DIB

Board Feet:
bf

Calculation History

Total Board Feet: 0 bf

Calculator

will enter the length of your log-in feet
the diameter at the small end inside the bark in inches

Results

the board foot estimate of the logs
Running Total: automatically sums all entries. Add more logs and use Copy or Download CSV to save your data. Use Clear History to reset the calculation log and the running total.

Scribner Decimal Rule Formula

The Scribner Decimal Rule estimates board feet in a log using this formula:

\[ \text{Board Feet} = 0.0494 \cdot D^2 \cdot L - 0.124 \cdot D \cdot L - 0.269 \cdot L \]

Where:

\( D \) = Diameter inside bark at the small end (in inches)
\( L \) = Length of the log (in feet)

Example Calculation

Given:

\( D = 14 \, \text{in} \)
\( L = 16 \, \text{ft} \)

Step-by-step:

\[ \begin{align*} \text{Board Feet} &= 0.0494 \cdot 14^2 \cdot 16 - 0.124 \cdot 14 \cdot 16 - 0.269 \cdot 16 \\ &= 0.0494 \cdot 196 \cdot 16 - 0.124 \cdot 224 - 4.304 \\ &= 154.4192 - 27.776 - 4.304 \\ &= 122.34 \end{align*} \]

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