MasterTool

Log Board Foot Calculator (Scribner scale)

Estimate log board-foot yield with the Scribner rule.

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What this tool does

Estimate log board-foot yield with the Scribner rule. Scribner is an estimated sawn-yield rule, not solid wood volume. International uses the common length-scaled ¼-inch approximation, not sectional official log tables.

How to use the Log Board Foot Calculator (Scribner scale)

  1. Enter or select small-end diameter inside bark in in.
  2. Enter or select log length in ft.
  3. Enter or select log count.
  4. Read the calculated result; change any measurement to compare alternatives.

Formula

BF=max(0,0.79×D²−2×D−4)×L/16
diameter
Small-end diameter inside bark (in, before metric conversion)
length
Log length (ft, before metric conversion)
count
Log count

Scribner is an estimated sawn-yield rule, not solid wood volume. International uses the common length-scaled ¼-inch approximation, not sectional official log tables.

Worked example

For log board foot calculator (scribner scale), the following measurements illustrate the exact method: Small-end diameter inside bark: 16; Log length: 16; Log count: 1.

Inputs

  • Small-end diameter inside bark16 in
  • Log length16 ft
  • Log count1

Result

  • Estimated board feet166.24
  • Yield per log166.24

Results explained

Estimated board feet
Estimated board feet from the formula above. Scribner is an estimated sawn-yield rule, not solid wood volume. International uses the common length-scaled ¼-inch approximation, not sectional official log tables.
Yield per log
Yield per log from the formula above. Scribner is an estimated sawn-yield rule, not solid wood volume. International uses the common length-scaled ¼-inch approximation, not sectional official log tables.

Frequently asked questions

Use the Scribner polynomial printed above with inside-bark small-end diameter.

Use actual measured thickness and width unless your supplier explicitly prices on nominal rough dimensions. A nominal 2 × 4 is typically 1.5 × 3.5 inches after surfacing.

No unless a waste input is shown. Add stock for end trimming, defects and kerf rather than treating the computed total as a guaranteed cut plan.

Length inputs with a unit can be switched to metric; internal formulas keep a consistent inch/foot basis. Board foot outputs remain board feet.

Taper, defects, kerf and mill practice change recovered yield; Scribner is not interchangeable with other log scales.