Estimate usable lumber from any log using the Doyle Rule formula.
Measure at the small end of the log, excluding bark.
Board feet by diameter (inches) and length (feet)
| Diameter ↓ / Length → |
|---|
* Values calculated using Doyle Rule: ((D − 4) / 4)² × L. Actual yield may vary based on log quality and sawing method.
Board Feet (Doyle) = ((D − 4) / 4)² × L
Where D = small-end diameter (inches) and L = length (feet)
((D−4)/4)² × L
Most common in Eastern US
(0.79D² − 2D − 4) × L/16
Used in Western US
(0.905D² − 1.2D) × L/16
Most accurate overall
The Doyle Rule is the industry standard in most of the Eastern United States and is the default in our calculator. It tends to underestimate board feet for smaller logs and overestimate for larger ones. The Scribner and International rules may provide more accurate estimates depending on your region and log size.
A board foot is the standard unit for measuring lumber volume. It equals a piece of wood 12 inches long, 12 inches wide, and 1 inch thick — or 144 cubic inches of material. When applied to raw logs, "log board feet" estimates the amount of usable lumber that can be sawn from a given log after accounting for taper, sawkerf, and waste.
Understanding log board feet is essential for landowners, loggers, sawmill operators, and lumber traders. It provides a standard way to price standing timber, negotiate log purchases, and plan milling operations with accuracy.
Estimate the monetary value of standing trees before harvest using board foot measurements.
Use standardized log rules to consistently measure and compare lumber yield across different logs.
Board foot calculations ensure transparent pricing between buyers, sellers, and mill operators.
Our calculator uses the Doyle Rule — the most widely accepted formula in the Eastern United States — to provide instant board foot estimates. Here's how to get started:
Measure the diameter of the log at the small end, inside the bark. This is called the "scaling diameter" and should be recorded in inches.
Record the total length of the log in feet. Standard sawlog lengths range from 8 to 16 feet, though longer logs can also be calculated.
Input your measurements into the calculator and click Calculate. The Doyle Rule formula is applied instantly to give your estimated board feet.
Review the board foot estimate along with approximate value. Use the reference table to compare different log sizes and plan your milling strategy.
The Doyle Rule provides an estimate based on ideal log conditions. Real-world logs with knots, rot, sweep, or crook will yield less usable lumber. For logs with visible defects, consider reducing the estimated board feet by 10–25% for more realistic planning.
The Doyle Rule is one of the oldest and most commonly used log scaling methods in North America. Developed in the early 1800s, it remains the standard measurement system for buying and selling timber across much of the Eastern United States.
The formula works by estimating the slab waste (the rounded outer portion of the log) and sawkerf (material lost to saw cuts). While it underestimates yield on small-diameter logs and slightly overestimates on large ones, its simplicity and widespread adoption make it the go-to method for most log transactions.
| Log Size | Doyle Accuracy | Notes |
|---|---|---|
| 6–10" diameter | Underestimates | May undercount by 20–40% |
| 12–18" diameter | Most Accurate | Closest to actual yield |
| 20–32" diameter | Overestimates | May overcount by 10–20% |
Board foot calculations are used across the forestry and woodworking industries. Here are common scenarios where accurate log scaling is critical:
Estimate standing timber value before contacting buyers or loggers.
Predict lumber output and plan milling schedules based on log inventory.
Track log yard volumes and maintain accurate stock records.
Negotiate fair prices with clear board foot measurements for each load.
Teach log scaling methods in forestry programs and certification courses.
Evaluate timber resources as part of property valuation and forest management plans.
Always measure the diameter at the small end of the log, inside the bark. This gives the most conservative and standardized measurement for scaling.
Board feet measure usable lumber, not firewood. For firewood, you'd typically use cords (128 cubic feet). However, knowing board feet can help decide whether a log is more valuable as lumber or firewood.
The Doyle Rule uses a fixed 4-inch deduction for slab waste regardless of log size. On small logs, this represents a larger percentage of total wood, leading to underestimates. For logs under 10 inches, consider the International ¼" Rule for better accuracy.
It depends on the tree's diameter, height, and number of usable logs. A single 16-foot log with a 20-inch diameter yields roughly 64 board feet by the Doyle Rule. Large hardwood trees can contain several hundred board feet across multiple logs.