Doyle Log Rule – board feet from the small-end diameter

The oldest log rule still in wide use in the southern and midwestern United States.

What is the Doyle Log Rule?

The Doyle log rule is a formula that estimates log volume in board feet (BF) from the small-end diameter inside bark in inches and the length in feet. It is simple, but it strongly underestimates lumber yield on small logs and overestimates it on very large ones.

Formula

BF = (D − 4)² · L / 16

D = small-end diameter inside bark in inches · L = length in feet. Diameters under 4 inches give 0. The 4-inch deduction stands for slabs and saw kerf.

Worked example

A log 16 inches at the small end and 16 feet long: BF = (16 − 4)² · 16 / 16 = 144 BF.

Where it is used

The southern and midwestern United States, hardwood log trade and many US sawmills.

Doyle vs Scribner vs International ¼″ ›

Frequently asked questions

Why does Doyle scale small logs so low?

It deducts a fixed 4 inches from the diameter. On a small log that is a large share of the diameter, so the result is far below the real lumber yield.

What is the difference between Doyle and Scribner?

A 16″ × 16 ft log scales 144 BF by Doyle and 160 BF by Scribner. The gap shrinks as the diameter grows, and on very large logs Doyle gives more.

Does the app scale Doyle offline?

Yes. The app always scales logs offline, in board feet and in m³.

Other log scaling methods

All 22 methods in the app ›

In your countryDoyle vs Scribner vs International ¼″Three US board foot rules, three different results for the same log. Clearly laid out, in numbers, with the reasons.BF · US · CA In your countrySmalian formulaWhen you cannot reach the middle of the log – on a deck or a truck – you measure both ends.m³ · US · CA In your countryScribner Decimal CA rule built by drawing boards into circles, today the standard for softwood logs in the western United States.BF · US · CA In your countryInternational ¼″ Log RuleIt allows for a ¼-inch kerf, shrinkage and log taper, so it comes closest to the real lumber yield.BF · US Huber formulaThe most widely used scaling method in Central Europe: one diameter at mid-length and the length.m³ · SK · CZ · DE · AT · FR · IE JAS (Japanese standard)The small-end diameter squared method, the standard for logs traded to Japan.m³ · JP Swedish scaling (toppmätning)Swedish sawmills pay by the small-end diameter: m³to is a cylinder from the top end.m³ · SE Hoppus formulaA traditional British rule still used in the tropical hardwood and teak trade.m³ · GB · IE · IN · GH · MY More methodsSTN 48 0009, ČSN 48 0009, Vermont, Universal (Daniels), Newton, GOST 2708-75, Brereton, Ontario Board Foot, Ontario Cubic, Roy, Alberta, BC Firmwood, Mid-girth, Guo Biao (GB/T 4814)All 22 methods ›