Doyle Log Rule Calculator

Diameter of the log (D) in inches:



Log length (L) in feet:



Calculate

Board Feet (BF):

The Doyle Log Rule is a popular method for estimating the amount of usable lumber that can be obtained from a log. This rule is used by loggers, sawmill operators, and foresters to calculate the board feet (BF) of a log based on its diameter and length. The Doyle Log Rule provides a quick way to determine how much lumber can be harvested from a log without needing complex calculations or specialized equipment.

The Doyle Log Rule formula takes into account the diameter of the log and the length of the log. By applying the formula, you can get an estimate of the board feet, which is essential for calculating the volume of wood and the potential profit from a logging operation.

The formula used in the Doyle Log Rule is:

• BF = ((D - 4)^2 * L) / 16

Where:

• BF = Board feet
• D = Diameter of the log in inches
• L = Length of the log in feet

Formula

To calculate the board feet of a log using the Doyle Log Rule, the formula is:

• BF = ((D - 4)² * L) / 16

Where:

• D is the diameter of the log, measured in inches.
• L is the length of the log, measured in feet.
• The formula subtracts 4 inches from the diameter to account for the bark and the irregularities on the outside of the log, as these areas are usually not usable for lumber production.

How to Use

1. Enter Diameter (D): Input the diameter of the log in inches. This should be measured at the small end of the log.
2. Enter Length (L): Input the length of the log in feet.
3. Click "Calculate": After entering both the diameter and the length, click the "Calculate" button to estimate the board feet.
4. View the Result: The calculator will display the board feet value in the result field.

Example

Let's say you have a log with a diameter of 12 inches and a length of 8 feet. Using the formula:

• BF = ((12 - 4)^2 * 8) / 16
• BF = (8^2 * 8) / 16
• BF = (64 * 8) / 16
• BF = 512 / 16
• BF = 32

So, a log with a diameter of 12 inches and a length of 8 feet would have approximately 32 board feet.

FAQs

1. What is the Doyle Log Rule? The Doyle Log Rule is a formula used to estimate the number of board feet in a log based on its diameter and length.
2. How accurate is the Doyle Log Rule? The Doyle Log Rule provides an estimate, but it tends to overestimate the board feet, especially for logs with larger diameters. It is a simple and quick method, but other rules, such as the Scribner Rule, may offer more accuracy.
3. What are board feet? A board foot is a unit of measurement used in the lumber industry to represent a volume of wood. One board foot is equal to a 1-foot length of wood with a 1-foot width and 1-inch thickness.
4. Why do we subtract 4 from the diameter in the formula? The subtraction of 4 inches accounts for the bark and the irregular outer portion of the log, which are not usable for milling.
5. Can I use the Doyle Log Rule for all types of logs? The Doyle Log Rule is mainly used for estimating board feet in softwood logs, but it can be applied to hardwood logs with reasonable accuracy.
6. What if my log is not perfectly cylindrical? The Doyle Log Rule assumes the log is roughly cylindrical. If the log is irregularly shaped, this can affect the accuracy of the estimate.
7. How do I measure the diameter of a log? Measure the diameter of the log at the small end, perpendicular to the length of the log.
8. How do I measure the length of the log? Measure the length of the log along its axis, from one end to the other, in feet.
9. What is the difference between the Doyle Log Rule and the Scribner Rule? The Doyle Log Rule is a simpler method that provides a quick estimate, but it tends to overestimate board feet, especially for larger logs. The Scribner Rule is more accurate, especially for smaller logs.
10. Can I use this calculator for logs of any size? Yes, the calculator works for logs of all sizes, but the accuracy of the result may vary based on the size and shape of the log.
11. How do I convert board feet to cubic feet? To convert board feet to cubic feet, divide the board feet by 12. For example, if you have 36 board feet, the equivalent volume in cubic feet is 36 / 12 = 3 cubic feet.
12. How do I calculate the total board feet for multiple logs? To calculate the total board feet for multiple logs, simply calculate the board feet for each log individually and add them together.
13. Can I use this calculator for estimating lumber in logs with unusual shapes? This calculator assumes that the log is cylindrical. For logs with unusual shapes, other formulas may provide a more accurate estimate.
14. What is the maximum diameter of a log for the Doyle Log Rule to work? The Doyle Log Rule can work for logs of any diameter, but the results become less accurate for very large logs (e.g., over 30 inches in diameter).
15. How does the length of the log affect the board feet calculation? The longer the log, the more board feet it will contain, as the formula takes into account both the diameter and the length of the log.
16. Can I use the Doyle Log Rule for logs with a diameter smaller than 4 inches? No, the formula is not valid for logs with a diameter smaller than 4 inches, as the outer portion of the log would be too small to mill into usable lumber.
17. How can I improve the accuracy of the estimate? Using a more precise formula, such as the Scribner Rule, or measuring logs at multiple points can improve accuracy.
18. Does the Doyle Log Rule account for the quality of the wood? The Doyle Log Rule does not account for the quality of the wood. It only provides an estimate based on diameter and length.
19. Can this calculator be used for all tree species? Yes, the Doyle Log Rule can be applied to most species of trees, though the amount of usable lumber may vary depending on the type of wood.
20. Is the Doyle Log Rule used worldwide? The Doyle Log Rule is widely used in North America, but other regions may use different methods for estimating board feet, such as the International 1/4 Inch Rule or the Scribner Rule.

Conclusion

The Doyle Log Rule provides a quick and easy way to estimate the amount of usable lumber in a log. While it is not always the most accurate method, it is widely used in the lumber industry and offers a convenient solution for estimating board feet. By entering the diameter and length of a log into the Doyle Log Rule calculator, you can quickly determine how much lumber can be obtained from the log, helping loggers and sawmill operators make more informed decisions.