Log Weight Calculator

Frequently Asked Questions

How accurate is the Doyle log rule?

Accurate for logs 16-24 inches in diameter. It underestimates yield on logs under 12 inches by about 20% or more. Use the International rule for small logs.

How heavy is a cord of dry oak?

A cord of dry red oak weighs about 3,500-4,500 lb (128 cubic feet stacked). Green oak can weigh 50-60% more.

Do I measure the small end or large end for the Doyle rule?

The small end, which is the narrower top end of the log. That is the standard convention for all log scaling rules.

Why does the log weigh more than the sawn lumber?

Sawdust, slabbing, and edging remove 35-50% of the volume. A modern sawmill recovers 50-65% of log volume as usable lumber.

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Estimates for informational purposes only.

Important Disclaimer: Estimates for informational purposes only.

This calculator provides estimates for informational purposes only. Results are based on assumptions and may not reflect actual outcomes. Consult qualified professionals in relevant fields before making important decisions based on these results.

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How This Calculator Works

A round log is modeled as a cylinder. Volume = pi x (radius_ft)^2 x length_ft, where the radius is converted from inches: radius_ft = (diameter_in / 2) / 12. Weight = volume x species density (lb/ft³).

The Doyle log rule estimates how many board feet of lumber can be sawn from the log: BF = ((D - 4)^2 x L) / 16, where D is the small-end diameter in inches and L is length in feet. The Doyle rule tends to underestimate yield on small logs (under 14 inches diameter) and is most accurate for large sawmill logs.

Densities are at approximately 12% moisture content. Green logs can weigh 30-60% more because they are saturated with water in the living cell walls.

Understanding Log Rules

A log rule is a formula used to estimate the board-foot yield of a round log before it is sawn. Different log rules give different answers because they make different assumptions about saw kerf and slabbing waste.

Doyle rule: BF = ((D-4)^2 x L) / 16. Simple but underestimates small logs significantly. Widely used in the eastern US for hardwood trade.

Scribner rule: Based on actual diagram measurements of the log cross-section. More accurate, especially for smaller logs. Common in the western US.

International 1/4-inch rule: Based on a series of cylinders inside the log. Generally gives the highest yield estimate and is considered the most accurate for small logs.

This calculator uses the Doyle rule since it is the most widely recognized and taught. Expect actual milled board footage to differ by 10-30% depending on the sawyer's skill and equipment.

Practical Tips

Use these guidelines when working with log weight estimates:

Always measure at the small end of the log for the Doyle rule - that is the standard convention.

Green logs can weigh double what a dry log of the same size weighs. If you are loading a truck or skidder, verify whether you need green or dry density.

Log weight is important for equipment sizing: most log splitters and log loaders have rated lift capacities. A large white oak log can easily exceed the lift rating of a small tractor.

Species density varies significantly within a species based on growth rate, location in the tree, and moisture. Use the weight here as an estimate - weigh critical loads directly.

FAQ

How accurate is the Doyle log rule?

Fairly accurate for logs 16-24 inches in diameter and 12-16 feet long. It significantly underestimates yield on logs under 12 inches diameter - a 10-inch log yields about 20% more board feet than Doyle predicts. For accurate purchasing, use the International 1/4-inch rule or have the log cruise-measured.

How heavy is a cord of wood?

A cord (128 cubic feet stacked) of dry hardwood weighs 2,000-5,000 lb depending on species. Oak runs about 3,500-4,500 lb per cord dry; pine and spruce are lighter at 2,000-2,800 lb. Green wood is heavier by 30-60%.

What does small-end diameter mean?

The small end is the top of the tree - the narrower end of the log. Log rules use small-end diameter because it determines the maximum board width that can be cut from the log without going outside the cylinder.

Why does a log weigh more than the boards sawn from it?

Sawdust and slabbing waste remove material. A well-equipped modern sawmill recovers 50-65% of log volume as usable lumber. The rest becomes sawdust, chips, slabs, and edgings.

Log Weight Calculator

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