What Is a Log Volume Calculator?
Use this Log Volume Calculator to estimate the total board feet in one or more logs. Enter the log diameter, log length, and number of logs, then choose the Doyle or Scribner log rule.
This calculator is useful for timber sales, sawmill planning, forestry, woodworking, and estimating the potential lumber yield from logs of the same size.
How to Use the Log Volume Calculator
Enter the following values:
- Diameter: Measure the log’s small-end diameter inside the bark.
- Length: Enter the log length in feet.
- Number of logs: Enter the quantity of logs with the same diameter and length.
- Log rule: Select either the Doyle or Scribner method.
The calculator returns the Total Board Feet for the selected log rule.
For logs with different diameters or lengths, calculate each group separately and add the results together.
What Is a Log Rule?
A log rule is a method for estimating how many board feet of lumber can be sawn from a round log. Different log rules can give different results for the same log because they use different assumptions about saw kerf, slab waste, taper, and usable lumber yield.
This calculator includes:
- Doyle Rule
- Scribner Decimal C Rule
Doyle Log Rule Formula
The Doyle log rule is a common method used to estimate the volume of lumber that can be sawn from a log. The Doyle rule tends to underestimate log volumes for smaller logs and overestimate for larger ones. Here's the formula and method to calculate the log volume using the Doyle log rule:
V=(D−4)2⋅16L
Board Feet=(4D−4)2×L
Where:
- 𝐷 is the diameter of the log in inches (measured at the small end, inside the bark).
- 𝐿 is the length of the log in feet.
Steps to Calculate Log Volume using Doyle Rule
- Measure the Diameter: Measure the diameter (D) of the log at the small end, inside the bark, in inches.
- Measure the Length: Measure the length (L) of the log in feet.
- Apply the Formula: Plug the values of D and L into the Doyle formula.
Example Calculation
Suppose you have a log with a diameter of 16 inches and a length of 12 feet:
- Diameter (D): 16 inches
- Length (L): 12 feet
Calculation:
Board Feet=(416−4)2×12
Board Feet=(412)2×12
Board Feet=(3)2×12
Board Feet=9×12
Board Feet=108
So, the log volume is estimated to be 108 board feet using the Doyle log rule.
Scribner Log Rule Formula
The Scribner rule is typically represented by a set of tables, but it can also be estimated with the following formula
v=16(0.79D2−2D−4)L
Where:
- 𝐷 is the diameter of the log in inches (measured at the small end, inside the bark).
- 𝐿 is the length of the log in feet.
Example Calculation
Suppose you have a log with a diameter of 16 inches and a length of 12 feet:
- Diameter (D): 16 inches
- Length (L): 12 feet
Calculation:
Board Feet = (((0.79 x 16 x 16) - (2 x 16) - 4) x 12 ) / 16
Board Feet = ((202.24 - 32 - 4) x 12 ) / 16
Board Feet = (166.24 x 12 ) /16
Board Feet = 1994.88 / 16
Board Feet = 124.68
Doyle Rule vs. Scribner Rule
The Doyle and Scribner rules can produce different board-foot estimates for the same log.
The Doyle Rule is simple and widely recognized, but it may estimate lower volumes for smaller logs and higher volumes for larger logs. The Scribner Rule uses a different yield estimate and may produce a different result.
Neither method measures the exact amount of finished lumber you will receive. Actual yield can vary because of log taper, defects, knots, rot, saw kerf, milling method, trim allowance, and lumber thickness.
Tips for Measuring Logs
- Measure the diameter at the small end of the log.
- Measure diameter inside the bark when using these log rules.
- Record length in feet.
- Use the same log rule used by the buyer or sawmill.
- Measure each log separately when the logs are not the same size.
- Round only according to the rules used by your timber buyer or local market.
Frequently Asked Questions
What does this Log Volume Calculator calculate?
It estimates the total board feet of logs using the Doyle or Scribner log rule.
What is board foot volume?
A board foot is a unit used to estimate the amount of lumber that can be sawn from a log. It is not the same as the log’s solid cubic volume.
Which diameter should I measure?
Measure the diameter at the small end of the log, inside the bark.
Why do Doyle and Scribner give different results?
Each rule uses different assumptions about sawmill waste, taper, and usable lumber yield. Use the method required by the buyer, mill, or timber contract.
Can I calculate multiple logs at once?
Yes, when the logs have the same diameter and length. Enter the number of identical logs to get the total board feet.
Is this the exact lumber yield from my log?
No. The result is an estimate. Actual lumber yield depends on log quality, defects, taper, milling equipment, saw kerf, and the final lumber dimensions.
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