Timber Volume Calculator

Each rule was built around different assumptions about saw kerf (the wood lost to the blade), taper, and slab waste. Doyle assumes the widest waste margin and consistently produces the lowest board-foot estimate on small logs — on a 16-inch log it can read 20-25% below Scribner and International. That gap closes as diameter increases, and Doyle's formula actually crosses over and reads *higher* than International on large logs (roughly 28-30 inches and up on a 16-foot log), because Doyle's fixed 4-inch slab deduction stops representing a realistic fraction of a big log's cross-section. Scribner sits in the middle across most of the range. None of the three is 'wrong'; they are different accounting conventions that a buyer or seller has agreed to use, and which one reads highest depends on the log's size, not just which rule is 'better.'

Use whichever rule your buyer or local mill actually pays on — that is the only number that matters commercially. Doyle remains common for hardwood sawtimber sales in the eastern and southern US, Scribner is traditional in much of the Pacific Northwest and Rocky Mountain West, and International 1/4-Inch is used by many public land agencies and increasingly by mills seeking a more accurate recovery estimate. If you are comparing offers from two buyers who use different rules, convert both to the same rule before comparing dollar figures. University forestry-extension log-scaling guides, such as the University of Tennessee's Understanding Log Scales and Log Rules publication, document all three formulas and their typical regional use in more detail.

Diameter matters far more. Because board feet scales roughly with the square of small-end diameter but only linearly with length, doubling a log's diameter raises its volume by roughly four times, while doubling its length only doubles it. A short, fat log routinely out-scales a long, thin one — this is why timber cruisers spend most of their measurement effort getting diameter right and treat length as a secondary correction.

Lumber recovery percentage compares the board-foot yield (already a lumber-industry unit that assumes 1-inch-thick boards) against the log's raw cubic volume converted to the same units. It comes in under 100% because sawing a round log into square-edged boards always leaves slabs, sawdust, and edging waste — a cylinder cannot be perfectly divided into rectangular boards. Recovery in roughly the 50-70% range is typical for mid-size sawlogs (it trends higher on longer, larger-diameter logs and lower on very short or narrow ones, since this simplified formula doesn't fully offset the geometry of a stubby log); real sawmills track this number closely because small gains in recovery translate directly into more lumber sold from the same log supply.

Not directly. This calculator scales a single log you already have measurements for — small-end diameter and length. Valuing standing timber requires a timber cruise: sampling many trees across a stand, estimating each tree's merchantable log length and diameter, and applying a volume table or rule like this one to each log, then summing and applying a stumpage price. Use this calculator as the per-log building block inside that larger process, not as a stand-level appraisal tool on its own.