Doyle Log RuleBoard Foot Volume Calculator
Most widely used log scaling rule in eastern USA. Calculates board foot volume from diameter and length. Instantly compare Doyle, Scribner, International Rule and IS 1902 India.
Why this calculation matters
Doyle under-reports small logs heavily. If your buyer quotes Doyle and you scale International, you are not discussing the same log.
Doyle Log Rule
Board Foot Volume Calculator
This picker does not change the answer. Board feet depends only on the dimensions you enter, not on the species — that is what makes it a rule rather than an estimate. The species is here so you can note it on a printout.
Diameter Inside Bark at the small end. Doyle is based on DIB.
Standard lengths: 8, 10, 12, 14, 16 ft. India IS: 1.8m to 6m.
Measured over bark. If your figure is already inside bark (DIB), set bark to 0.
Enter 0 if measuring DIB directly.
| Log Rule | Formula | BF per log | Note |
|---|
About Doyle Log Rule
The Doyle Rule is the most widely used log scaling standard in eastern and southern United States. Developed by Edward Doyle in the 1820s, it estimates the number of 1-inch lumber boards that can be sawn from a log. Despite known underestimation for small logs, it remains the industry standard across North America for hardwood log purchases. Many buyers still carry a printed Doyle log scale chart in the yard — this tool replaces it, converting any log to board feet on the spot with bark and taper handled for you.
Doyle scale chart (printable quick reference)
Board feet by small-end diameter inside bark, from the Doyle formula ((D−4)²÷16)×L:
| Diameter | 8 ft log | 12 ft log | 16 ft log |
|---|---|---|---|
| 10" | 18 | 27 | 36 |
| 12" | 32 | 48 | 64 |
| 14" | 50 | 75 | 100 |
| 16" | 72 | 108 | 144 |
| 18" | 98 | 147 | 196 |
| 20" | 128 | 192 | 256 |
| 22" | 162 | 243 | 324 |
| 24" | 200 | 300 | 400 |
| 26" | 242 | 363 | 484 |
| 28" | 288 | 432 | 576 |
| 30" | 338 | 507 | 676 |
Print this if you like — but the calculator above also handles bark deduction, taper and odd lengths that no chart covers.
Where Is This Used?
Formulas Used
Doyle: BF = ((D - 4)^2 / 16) x L D = DIB inches, L = length feetScribner: BF = (0.79 x D^2 - 2xD - 4) x (L/16)International 1/4": BF = Grosenbaugh polynomial (0.04976191LD² + ...)IS 1902 India: V = pi x (D/200)^2 x L m3, D in cm, L in mConversion: 1 m3 = 423.78 BF | 1 BF = 2359 cm3How the calculation works
Four inches are taken off the diameter first — that is the rule’s fixed allowance for the slabs sawn off the outside. A quarter of what remains is squared and multiplied by the length. The flat four-inch deduction is why Doyle reads so low on small logs: on a ten-inch log it removes almost half the diameter.
Show the formula
Board feet = ((D - 4) / 4)^2 x L, with D the small-end diameter inside bark in inches and L the log length in feet. Scribner and International figures shown alongside use their own published formulas.Published Doyle rule, unchanged since before 1850. The 4-inch slab allowance is too large for small logs and too small for large ones — that bias is in the rule itself, not in this calculator.
References and what each one provides
- USDA Wood Handbook (FPL GTR-190)USDA Forest Products LaboratoryPublished density, moisture relationships, shrinkage coefficients and mechanical properties for a wide range of species. The reference dataset behind most wood-property figures on this site.
Unverified values are marked as such rather than presented as sourced.
Limitations of this calculation
Applies the Doyle formula as published. It does not account for actual mill recovery, taper, sawing pattern, or kerf other than the fixed allowance built into the rule.
Do not use this for Sale settlement unless both parties have agreed Doyle in writing. It reads materially low on small logs.
Figures are engineering estimates from the inputs and assumptions shown. Verify against the actual material and, where the result affects structure or safety, against a qualified professional.
- Doyle log rule (published rule)
- Taper geometry and bark deduction
Formula checked against the sources above by an automated regression test (tests/test-calculators.js) that derives each expected value independently of this page. Last reviewed .
How to use this tool
- Enter the log measurements below, then press Calculate.
- Fill in small-end diameter, log length, number of logs, bark thickness each side.
- Press Calculate.
Worked example
Common mistakes to avoid
- Using Doyle on small logs and wondering why the mill 'overruns'. Doyle badly under-scales logs below about 14 inches.
- Measuring diameter at the big end. All the common rules use the small end.
- Comparing a Doyle price per BF with a Scribner price per BF. Same log, different BF — the rules are not interchangeable.
Frequently Asked Questions
Wood species data
Density, hardness and movement for 60 timbers