Doyle 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.

Short answer

On small and medium logs Doyle gives the least, Scribner more and International ¼″ the most – and International comes closest to the real lumber yield. A 16″ × 16 ft log scales 144, 160 and 180 board feet. As the diameter grows the gaps shrink, and on very large logs Doyle even gives more than Scribner.

Board feet of a 16 ft log

Doyle and International ¼″ are computed from their formulas (International rounded to 5 BF like the official table), Scribner from the Decimal C table. Diameter is at the small end, inside bark.

Diameter	Doyle	Scribner Dec. C	International ¼″	Doyle / International
8″ (20.3 cm)	16	30	40	40 %
12″ (30.5 cm)	64	80	95	67 %
16″ (40.6 cm)	144	160	180	80 %
20″ (50.8 cm)	256	280	290	88 %

Why they differ

Doyle deducts a fixed 4 inches from the diameter for slabs and kerf – a big loss on small logs, so it underestimates them heavily. Scribner was made by drawing boards into a circle but ignores log taper. International ¼″ allows for a ¼-inch kerf, shrinkage and a taper of ½ inch per 4 feet, which makes it the most accurate.

Who uses which rule

Doyle: the southern and midwestern US, hardwood logs. Scribner Decimal C: the western US and Canada, softwood logs and USDA Forest Service timber sales. International ¼″: the north-eastern US, several state forestry agencies and research.

Frequently asked questions

Which rule is better for the seller?

For typical logs, International ¼″, because it gives the highest volume. Doyle favours the buyer.

Why do US sawmills still use Doyle?

Tradition – and on small logs it gives a low scale, so the difference between the scale and the actual lumber yield (overrun) stays with the mill.

Can board feet be converted to m³?

Only approximately. Depending on the rule and diameter, 1,000 board feet of logs is roughly 4–7 m³. For an exact figure, measure the log and calculate both ways – the app does it at once.

Does the app calculate all three rules?

Yes, offline too – Doyle, Scribner Decimal C, International ¼″ and 19 more methods, in board feet and m³.

Other log scaling methods

All 22 methods in the app ›

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 countryDoyle Log RuleThe oldest log rule still in wide use in the southern and midwestern United States.BF · US 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 ›