Log Board Foot Calculator
How many board feet of lumber a log will scale, from its small-end diameter and length, by all three common U.S. log rules side by side, for timber sales, sawmilling and firewood logs.
Doyle: (diameter − 4)² × length ÷ 16. Scribner and International ¼ in rules give more for small logs. A 16 in × 16 ft log scales 144 bd ft (Doyle), 166 (Scribner) and 181 (International ¼ in). Measure the diameter inside the bark at the small end.
Board feet in a 16 ft log
| Small-end diameter | Doyle | Scribner | International ¼ in |
|---|---|---|---|
| 10 in | 36 | 55 | 65 |
| 12 in | 64 | 86 | 97 |
| 14 in | 100 | 123 | 136 |
| 16 in | 144 | 166 | 181 |
| 18 in | 196 | 216 | 232 |
| 20 in | 256 | 272 | 290 |
| 24 in | 400 | 403 | 424 |
| 28 in | 576 | 559 | 585 |
Which log rule?
- Doyle: common in the South and East; underestimates small logs, so sellers of small timber get less.
- Scribner: common in the West; closer to actual sawn yield for mid-size logs.
- International ¼ in: the most accurate for real mill yield and the standard for many state and federal timber sales.
Ask which rule a buyer uses before comparing offers.
Frequently asked questions
How do you calculate board feet in a log?
Measure the diameter inside the bark at the small end in inches and the length in feet, then apply a log rule. With Doyle: (diameter − 4)² × length ÷ 16. A 20 in × 12 ft log is (16)² × 12 ÷ 16 = 192 bd ft.
Why do log rules give different answers?
Each rule makes different assumptions about saw kerf, slabs and taper. Doyle subtracts a large allowance, so small logs scale low; International ¼ in models sawing more closely.
How many board feet in a 16 inch log?
A 16 in log 16 ft long scales about 144 bd ft by Doyle, 166 by Scribner and 181 by International ¼ in.
Where do I measure log diameter?
At the small end, inside the bark, across the average diameter. Lengths usually include 3–6 in of trim allowance that isn't scaled.
How many board feet in a tree?
Scale each log from the tree separately (usually 8–16 ft lengths up to a merchantable top diameter) and add them up. Foresters use volume tables based on diameter at breast height and merchantable height.
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Doyle rule: (D − 4)² × L ÷ 16. Scribner: the common formula approximation (0.79D² − 2D − 4) × L ÷ 16. International ¼ in: 0.22D² − 0.71D per 4 ft section, diameter increasing ½ in per section for taper, × 0.905 for a ¼ in saw kerf. These are standard forestry formulas; official scaling follows your state's rules.