Log Board Foot Calculator — Doyle, Scribner & International Log Scale
Enter the small-end diameter (DIB) and log length to estimate board feet in a log. Compare Doyle, Scribner, and International 1/4" rules side by side.
Measure at the small end, inside the bark.
Show rule comparison
64.00
Board Feet
Rule comparison
Percent values show the difference compared to Doyle.
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How to Measure a Log for Board Feet
The inputs are simple, but measuring the right spot matters. Use DIB (diameter inside bark) at the small end for the most consistent results.
Tip: If the bark is thick or rough, measure inside bark (DIB) when you can.
- 1
Step 1 — Measure the Small-End Diameter (DIB)
Measure the diameter on the small end of the log, inside the bark. If you only have outside-bark diameter, your estimate may run high.
- 2
Step 2 — Measure the Log Length
Measure the usable length in feet (for example, 8–20 ft). Use the same length you expect the mill to scale.
- 3
Step 3 — Pick a Log Rule
Different regions use different rules. Doyle is common in the eastern U.S., Scribner is often used as a mid-range estimate, and International 1/4" is generally the most consistent.
Understanding Log Scaling Rules
Log rules estimate how much lumber you can saw from a log. The same log can scale very differently depending on the rule.
Doyle Log Rule
A simple, traditional rule that’s widely used. It often underestimates small logs because the slab allowance is large. Buyers and sellers often price with that bias in mind.
Scribner Log Rule
Originally based on boards drawn from logs. It can be closer than Doyle on mid-size logs, but it doesn’t fully account for taper and can vary from modern mill yield.
International 1/4-Inch Rule
Often considered the most consistent of the three. It’s based on saw-kerf and taper assumptions and tends to track modern sawn yield better than Doyle.
Log Board Feet Quick Reference
Common diameters × lengths. Switch rules to see how estimates change.
| Diameter (in) | 8' | 10' | 12' | 14' | 16' |
|---|---|---|---|---|---|
| 8" | 8.00 | 10.00 | 12.00 | 14.00 | 16.00 |
| 10" | 18.00 | 22.50 | 27.00 | 31.50 | 36.00 |
| 12" | 32.00 | 40.00 | 48.00 | 56.00 | 64.00 |
| 14" | 50.00 | 62.50 | 75.00 | 87.50 | 100.00 |
| 16" | 72.00 | 90.00 | 108.00 | 126.00 | 144.00 |
8" Diameter
DIB at small end
8'
8.00
10'
10.00
12'
12.00
14'
14.00
16'
16.00
10" Diameter
DIB at small end
8'
18.00
10'
22.50
12'
27.00
14'
31.50
16'
36.00
12" Diameter
DIB at small end
8'
32.00
10'
40.00
12'
48.00
14'
56.00
16'
64.00
14" Diameter
DIB at small end
8'
50.00
10'
62.50
12'
75.00
14'
87.50
16'
100.00
16" Diameter
DIB at small end
8'
72.00
10'
90.00
12'
108.00
14'
126.00
16'
144.00
All values assume DIB at the small end and length in feet. Results are estimates, not mill guarantees.
Common Mistakes to Avoid
Log scaling is sensitive to measurement details.
Measuring outside bark instead of DIB
Most log rules assume DIB (diameter inside bark) at the small end. Using outside-bark diameter can overestimate yield—especially on thick-bark species.
Measuring the wrong end
Measure the small end, not the large end. Using the large end can inflate estimates because taper is real.
Using the wrong rule for your region
Prices and expectations are tied to local rules. Confirm whether your buyer uses Doyle, Scribner, or International 1/4" before you compare numbers.
Disclaimer
This calculator provides an estimate for informational purposes. Real-world lumber yield depends on species, defects, taper, mill equipment, kerf, and local scaling practices. Always confirm the log rule, measurement method (DIB vs outside bark), and rounding conventions with your buyer or mill.
Sources
- University of Tennessee Extension — PB1650: Understanding Log Scales and Log Rules (Scribner & International formulas).
- USDA Forest Service — National Forest Log Scaling Handbook (measurement and scaling guidance).
- International 1/4" rule coefficients are commonly published as a continuous-length approximation (Grosenbaugh-style polynomial fit to rule tables).
Frequently Asked Questions
You measure the small-end diameter inside bark (DIB) in inches and the log length in feet, then apply a log rule. For example, the Doyle rule uses: BF = (D − 4)² × L ÷ 16. Other common rules include Scribner and International 1/4-inch, which often give higher estimates for the same log.