Resources · Calculators · Pine
Doyle board-feet calculator
Small-end diameter inside bark, length in feet. Doyle is what a lot of Southern mills still talk.
How to measure the log
D is small-end diameter inside the bark, in inches, across the cut. Not DBH on the stump, not the big end. Average two readings if it’s oval. L is length in feet, the log as it will be scaled. Doyle punishes small logs: a 10-inch 16-footer is only 36 board-feet on Doyle.
Same log, three rules
Illustrative calculator example, not a mill scale. Take one log with a 10-inch small-end diameter and 16 feet of length. The tool returns Doyle 36 board-feet, Scribner approximation 55 board-feet, and International ¼-inch about 60 (59.6 rounds to 60 on the screen). The log did not gain wood. Doyle, Scribner, and International estimate usable board-feet differently. Ask which rule and which table the buyer uses before you compare a quote.
The form opens on a 16-inch by 16-foot log. Calculate on that default and you get the wider log: Doyle 144, Scribner approximation 166, International about 180 (179.8 rounds to 180). Type 10 in the diameter box to see the small-log gap. Same log, different rule, either way. These are calculator estimates.
| Rule | 10 in × 16 ft | 16 in × 16 ft |
|---|---|---|
| Doyle | 36 bf | 144 bf |
| Scribner (approx.) | 55 bf | 166 bf |
| International ¼-inch | 60 bf | 180 bf |
Why small logs open a bigger gap
Doyle subtracts 4 inches before it squares the diameter, so a small pine gets penalized hard. The Scribner figure on this page is the common approximation (0.79D² − 2D − 4) × L/16, and it often reads higher than Doyle on small logs. Often is not a guarantee. Species, taper, defects, kerf, trim, the mill’s printed table, and how they scale the log all move a real settlement.
Measure once, then match the buyer’s rule
Measure the small end inside the bark. That is not DBH on a standing tree, and it is not the large end. If the cut is oval, average two readings taken across each other. Record length in feet. Put only logs of the same diameter and length in “how many like that.”
Before a sale, ask the buyer whether they scale Doyle, Scribner, International ¼-inch, or a mill’s printed table, and whether diameter is inside bark at the small end. Compare an estimate only when the rule and the measurements match. Output here is planning math, not a mill ticket and not a timber cruise. Write the diameters on the log scale card at the deck. The rest of the sheets are on the field sheet page.
Questions
What is the Doyle rule?
Doyle board feet = (D − 4)² × L / 16. D is small-end diameter inside the bark, in inches. L is length in feet. It is the scale a lot of Southern mills still talk.
Doyle vs Scribner — which should I use?
Use the rule the buyer is paying on. Doyle underestimates small logs; Scribner usually runs taller on small pine. This page shows Doyle, a Scribner approximation (0.79D² − 2D − 4) × L/16, and International ¼-inch. It is not a mill’s printed table.
Does this work for short logs under 8 feet?
Yes. Length is in feet, and the form accepts logs from 4 feet up, so a short log under 8 feet still scales with L on Doyle, Scribner, and International.
Why is Scribner higher than Doyle on the same small log?
They are different estimating rules. Doyle subtracts 4 inches before squaring, which penalizes small diameters. The Scribner value here is a common approximation and often runs higher on small pine. Use the buyer’s rule for a quote.
What should I ask a timber buyer before using a board-feet estimate?
Ask whether the buyer scales Doyle, Scribner, International ¼-inch, or a mill’s printed table, and whether diameter is measured inside bark at the small end. Compare estimates only when the rule and the measurements match.
Does a higher Scribner number mean the log contains more wood?
No. Doyle, Scribner, and International are different board-foot estimates for the same log. A mill’s scale, defects, taper, trim, and the settlement terms control an actual sale.
Is small-end diameter the same as DBH?
No. DBH is a standing-tree measurement. This calculator wants the cut log’s small-end diameter inside the bark, in inches.
Can I use this as a mill ticket or timber cruise?
No. It is planning math. Use the buyer’s printed table or a professional cruise when a sale depends on the number.
Planning only. Doyle = (D−4)² × L/16. Scribner here is the common 0.79D²−2D−4 approximation, not a mill’s printed table. Not a timber cruise.
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Words used here
Doyle log ruleScribner log ruleBoard-foot
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