Doyle Log Scale Calculator
The Doyle rule is the most common way to estimate the board feet of lumber a log will yield in the eastern and southern US. Measure the diameter inside the bark on the small end of the log and its length, then total as many logs as you have.
Your measurements
Measured inside the bark on the small end of the log.
Per log
- Board feet each
- 144 bd ft
- Log size
- 16 in × 16 ft
Board feet (Doyle)
144 bd ft
Estimates only. Verify against your supplier's coverage figures before ordering.
The formula
Board feet = ((Diameter − 4)² ÷ 16) × Length ft × Logs
Example: A 16 in × 16 ft log = ((16 − 4)² ÷ 16) × 16 = (144 ÷ 16) × 16 = 144 board feet (Doyle).
How it works
- 1Measure the diameter inside the bark on the small end of the log, in inches.
- 2Subtract 4 in (an allowance for slab and saw-kerf waste), square it, then divide by 16.
- 3Multiply by the log length in feet to get board feet for one log.
- 4Multiply by the number of logs for the total, and by a price per MBF (1,000 bd ft) for value.
Frequently asked questions
Why does the Doyle scale subtract 4 inches?
The 4-inch deduction approximates the slabs and sawdust lost when a round log is squared into boards. Because it's a fixed allowance, Doyle underestimates small-diameter logs and over-credits large ones.
Is the Doyle scale accurate?
It's an estimate. Doyle is the standard in the eastern and southern US but reads low on small logs; the Scribner and International 1/4-inch rules give different (often higher) numbers. Always confirm which scale your buyer or mill uses.