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Doyle log scale estimate

Estimate gross board-foot scale for a log using the named Doyle rule and the measured small-end inside-bark diameter.

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Example inputs · U.S. customary units

A 16 in diameter, 16 ft log. Before using the result, confirm that the purchaser uses the Doyle rule and measure the small end inside bark.

Example: 16 in.

Example: 16 ft.

Results

Ready to calculate

Enter your values, then choose Calculate. Your results will appear here.

How to use doyle log scale estimate

What this calculation does

The Doyle rule is a named gross log-scale estimate based on the small-end diameter inside bark and the log length.

Measure the small end inside bark, enter the log length in feet, and confirm that the purchaser uses this named rule.

Enter the measurements

  1. Small-end diameter inside bark: Measure diameter inside bark at the small end.
  2. Log length: Use the measured log length in feet.

Formula and variables

Doyle gross scale (BF) = (small-end inside-bark diameter in inches − 4)² × log length in feet ÷ 16.

Subtract four inches from the small-end diameter, square the difference, multiply by log length, then divide by sixteen.

Read the result

The entered log produces a gross Doyle estimate of 144 board feet, before any defect or transaction deductions.

Worked example

Inputs: 16 in small-end inside-bark diameter and 16 ft log length

  1. Diameter adjustment = 16−4 = 12 in; square = 12² = 144.
  2. Doyle scale = 144×16÷16 = 144 BF.

Expected result: 144 BF gross Doyle scale estimate

Frequently asked questions

Is this exact lumber recovery?

No. It is a gross named-rule scale, not exact volume or guaranteed merchantable lumber.

Can I compare it with another log rule?

Only after applying the same dimensions and understanding that each rule may estimate differently.

Conditions, presets and technical notes

Uses the named Doyle rule and small-end inside-bark diameter. Diameter must exceed 4 in; the result is gross rule-based scale, not exact solid volume or guaranteed merchantable/payable lumber. Defect deductions, local transaction practices and other log rules are outside this calculator.

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