Log Board Foot Calculator
Which log rule should you use?
Log scaling estimates how much lumber a sawmill can cut from a log, and three rules dominate. Doyle is the most common in the eastern US and at most Kentucky mills — its formula, (D−4)² × L ÷ 16, deliberately under-scales small logs (the "Doyle discount"), which is why loggers grumble about it and mills like it. Scribner comes from diagramming boards inside a circle and lands in the middle. International ¼-inch is the most accurate of the three — it accounts for saw kerf and log taper — and is what state agencies and foresters usually use. Same log, three different numbers: a 16-inch, 12-foot log scales 108 bf Doyle, about 119 bf Scribner, and roughly 135 bf International. That spread is why you should always know which rule a price is quoted in before selling or buying logs.
Measure the diameter inside the bark at the small end, average of two measurements if the log isn't round. Once your logs become lumber, our board foot calculator takes over — and the lumber weight calculator tells you what the haul weighs.
Doyle log scale chart
Board feet by the Doyle rule, from (D − 4)² × L ÷ 16, where D is the small-end diameter inside the bark in inches and L is the log length in feet. Find the diameter on the left and the length across the top. Doyle under-scales small logs heavily, so a buyer scaling by Doyle gets more lumber than the scale shows on anything under about 20 inches. Use the calculator above to compare it with Scribner and International ¼".
| Diameter | 8 ft | 10 ft | 12 ft | 14 ft | 16 ft |
|---|---|---|---|---|---|
| 8" | 8 | 10 | 12 | 14 | 16 |
| 10" | 18 | 22 | 27 | 32 | 36 |
| 12" | 32 | 40 | 48 | 56 | 64 |
| 14" | 50 | 62 | 75 | 88 | 100 |
| 16" | 72 | 90 | 108 | 126 | 144 |
| 18" | 98 | 122 | 147 | 172 | 196 |
| 20" | 128 | 160 | 192 | 224 | 256 |
| 22" | 162 | 202 | 243 | 284 | 324 |
| 24" | 200 | 250 | 300 | 350 | 400 |
| 26" | 242 | 302 | 363 | 424 | 484 |
| 28" | 288 | 360 | 432 | 504 | 576 |
| 30" | 338 | 422 | 507 | 592 | 676 |
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Frequently Asked Questions
How many board feet are in a log?
Measure the diameter inside the bark at the small end and the log length, then apply a log rule. By Doyle — the most common rule — a 16-inch, 12-foot log scales (16−4)² × 12 ÷ 16 = 108 board feet. Scribner and International ¼" give higher estimates for the same log, especially on small diameters.
What is the difference between Doyle and Scribner?
Doyle uses a simple formula that heavily under-estimates small logs, favoring the buyer; Scribner is based on diagrams of boards drawn inside the log's circle and runs closer to actual yield. On logs above roughly 28 inches the two converge. Always confirm which rule a mill quotes.
Why does the small-end diameter matter?
A sawmill can only cut full-length boards from the cylinder defined by the log's narrow end — the taper beyond it becomes shorter pieces and slabs. All three standard rules therefore scale from the small-end diameter measured inside the bark.
How do you read a Doyle log scale?
Find the small-end diameter inside the bark in the left column and the log length across the top. Where they meet is the board feet by the Doyle rule. A 16-inch log 16 feet long scales 144 board feet.