Spike's Calculators


Sweep Deduction Calculator

Log sweep deduction, using the Scribner Decimal C log rule for estimating board foot volume of the log.

One inch of sweep is allowed without a deduction of volume for logs smaller than 12 feet, 2 inches of sweep are allowed without a volume deduction in logs of 12 feet or larger in length.

Log Sweep
Example calculation:
log length of 16 feet
a log diameter of 22 inches measured inside bark on the small end of the log
the log sweeps 9 inches
Scribner Decimal C gross volume = 340 board feet (34 decimal)
9 - 2 = 7 ÷ 22 = 0.318 * 34 = 11 rounded
34 - 11 = 23
Net volume = 230 board feet

Sweep Deduction using Scribner Decimal C

Length of Log in Feet ft
Log Small End in Inches inch
Sweep inch


Gross Board Foot Volume bf
Deduction Ammount bf
Net Board Foot Volume bf


  1. enter the length of the log in feet
  2. the diameter of log in inches measured on the small end, inside the bark
  3. sweep amount in inches


  1. gross volume of the log in board feet
  2. amount to be deducted based on sweep amount, in board feet
  3. net volume of the log in board feet
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