Understanding Doyle Scaling
The Doyle log scale estimates sawn lumber from a round log. It uses the small end diameter and the usable log length. The rule is simple. It also carries a strong assumption. Four inches are removed from diameter before squaring. That allowance represents slabs, edging, and saw kerf. Because of that deduction, the rule often gives low numbers for small logs. It may look more generous on large logs.
Why This Calculator Helps
Hand scaling is fast when logs match a chart. Real work often needs more options. A buyer may handle several logs. A sawyer may deduct sweep, rot, shake, or metal risk. A seller may need a price estimate in board feet or MBF. This tool combines those steps in one place. It accepts outside bark or inside bark diameter. It can subtract bark thickness from both sides. It also applies defect allowance, trim deduction, quantity, and price.
Practical Measurement Tips
Measure diameter at the small end of the log. Use inches. Try to measure inside bark when possible. If you measure outside bark, enter bark thickness per side. Keep length in feet. Use the merchantable length, not the total rough stem length. Exclude unusable ends. Keep defect percent realistic. Severe sweep or rot should be judged before pricing.
Reading the Results
Gross board feet shows the rule estimate before defects. Net board feet applies your defect allowance. Total net board feet multiplies net footage by quantity. MBF converts the total to thousands of board feet. Estimated value uses the price per MBF. The target log count helps when you need enough logs for a planned order.
Limits and Best Use
The Doyle scale is an estimate. It does not replace local grading, mill recovery, or a written timber contract. Species, taper, sawing pattern, blade thickness, and operator skill can change final yield. Use the result for planning, comparison, and conversation. For payment, follow the rule required by your mill, forester, buyer, or local market.
Good Record Keeping
Save each result after changing inputs. Export files help compare loads and jobs. Keep notes on species, grade, moisture, and buyer terms. These details explain why the same scale may produce different money in different sales later.