Log Board Foot Calculator

Estimate volume using Standard Geometric & Doyle Log Rules

Calculation Results

Standard Geometric Rule

0.00 BF

0.00 BF per log

Doyle Log Rule

0.00 BF

0.00 BF per log

Calculation Breakdown

how much lumber can you get from your trees?

Log board feet provides an estimate of the usable timber in a tree prior to harvesting. Calculated by multiplying a log's length and diameter by a specific scaling factor which accounts for taper and natural imperfections this metric determines the approximate lumber yield and total value of standing timber.

To evaluate the board footage using the Doyle Log Rule formula, we calculate the result step-by-step:

The Doyle Log Rule formula is:

$$\text{Board Footage} = \left(\frac{D - 4}{4}\right)^2 \times L$$

Given:

Diameter ($D$) = $10\text{ inches}$
Length ($L$) = $17\text{ feet}$

Subtract 4 from diameter ($D$):$$10 - 4 = 6$$
Divide by 4:$$\frac{6}{4} = 1.5$$
Square the value:$$1.5^2 = 2.25$$
Multiply by length ($L$):$$2.25 \times 17 = 38.25$$

Your step-by-step calculation and final value of 38.25 board feet are correct.

Log Volume Calculator Instructions Guide

Sizing the Diameter: Measure inside the bark at the narrower end of the log. For logs that are not perfectly round, take two cross-sectional measurements at right angles and use their average.

Determining Length: Round length measurements down to the nearest whole foot, ignoring any remaining inches. Hardwood logs strictly follow this rule, whereas softwood logs are typically rounded down to the nearest even foot (such as 8, 10, or 12 feet).

Log Count Entry: Input the total number of logs using whole numbers only do not use fractions or decimal places.

Selecting a Log Scale: Choose one of the three available log measurement systems before running the calculation.

Methodology Details: Additional technical resources and details regarding WOODWEB's calculation methods are accessible through the provided links.

FAQs

To calculate board feet from a log, you need two basic measurements: the small-end diameter inside the bark (D, in inches) and the log length (L, in feet). Once you have those, you apply one of three standard industry log scaling formulas:

1. Doyle Rule (Most common for hardwoods)

Formula: Board Feet = ((D - 4) ÷ 4)² × L
Example: For a 16-inch diameter, 12-foot long log: ((16 - 4) ÷ 4)² × 12 = (12 ÷ 4)² × 12 = (3)² × 12 = 108 board feet.
Note: Tends to underestimate yield on small logs under 20 inches.

2. International 1/4-Inch Rule (Most accurate for actual sawmill output)

Formula: Board Feet = (0.22 × D² - 0.71 × D) × (L ÷ 4)
Account for saw kerf and taper to give the closest estimate to actual cut lumber.

3. Scribner Rule (Common for softwoods and timber sales)

Based on physical diagrams of how many 1-inch boards fit inside a log rather than a simple formula. Typically looked up on a scaling chart.

3 Key Measurement Steps:

Diameter (D): Measure across the smallest end of the log inside the bark. If the log is oval, average the widest and narrowest diameters.
Length (L): Measure the log's length in feet, rounding down to the nearest foot (or even foot, depending on mill standards).
Defects: Subtract a percentage of volume if the log has visible rot, severe curvature, or deep cracks.

Watch this video for a practical demonstration of how to accurately measure log diameter and length with a scaling stick.

The board foot yield of a 24-inch log depends on its total length and the scale applied, with measurements taken inside the bark at the narrow end. For instance, a 16-foot log produces approximately 224 board feet using the Doyle Rule and 255 board feet with the International 1/4-inch Rule, whereas a 12-foot log yields about 168 to 190 board feet, and a 10-foot log yields roughly 140 to 155 board feet. However, final recovered lumber totals will ultimately vary depending on factors such as saw blade kerf width, mill efficiency, and the presence of defects like rot or curvature.

Because a board foot measures volume (144 cubic inches, or 12′′×12′′×1′′) rather than surface area, 200 board feet covers 200 square feet at 1 inch thick, 100 square feet at 2 inches thick, 66.7 square feet at 3 inches thick, and 50 square feet at 4 inches thick. When ordering lumber for projects like flooring or decking, you should also factor in waste from cutting, milling, and fitting. Standard projects require an extra 10% to 15% of material, diagonal layouts or lower-grade lumber need 20% to 25% extra, and tongue-and-groove milling reduces face width coverage by roughly 10%.

Because a board foot measures volume (144 cubic inches) rather than surface area, the total square footage 200 board feet will cover depends entirely on the thickness of the boards used. At 1 inch thick, 200 board feet covers 200 square feet; at 2 inches thick, it covers 100 square feet; at 3 inches thick, it covers 66.7 square feet; and at 4 inches thick, it covers 50 square feet. When planning coverage for projects like flooring, decking, or paneling, you must also factor in material lost during milling, cutting, and fitting. Standard installations require an extra 10% to 15% of material, diagonal layouts or lower-grade lumber need an additional 20% to 25%, and tongue-and-groove milling reduces usable face width by roughly 10%.

A standard 2x4x8 ft piece of lumber contains 5.33 board feet. In the lumber industry, this is calculated using nominal dimensions through the formula (Thickness in inches × Width in inches × Length in feet) ÷ 12, which gives (2 × 4 × 8) ÷ 12 = 5.33 board feet.

While a finished 2x4 is milled down to actual dimensions of 1.5 inches by 3.5 inches (yielding about 3.5 board feet of real wood volume), suppliers and retailers always quote and price lumber using nominal measurements.

A 12-foot 2x4 contains 8 board feet under standard industry rules.

Calculated using nominal dimensions with the formula (Thickness in inches × Width in inches × Length in feet) ÷ 12, the math works out to (2 × 4 × 12) ÷ 12 = 8 board feet. While the true physical wood volume yields 5.25 board feet based on actual milled dimensions (1.5 inches × 3.5 inches), suppliers and retailers consistently quote and price lumber using nominal measurements.

The standard formula for calculating board footage using length in feet is:

Board Feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12

If all three dimensions are measured in inches, the formula is:

Board Feet = (Thickness in inches × Width in inches × Length in inches) ÷ 144

One board foot represents 144 cubic inches of wood volume, which is equivalent to a piece measuring 1 inch thick, 12 inches wide, and 1 foot long. For example, a board that is 2 inches thick, 6 inches wide, and 10 feet long equals 10 board feet: (2 × 6 × 10) ÷ 12 = 10.

A standard 2x4x10 piece of lumber contains 6.67 board feet.

Using the industry-standard nominal calculation formula, (Thickness in inches × Width in inches × Length in feet) ÷ 12, the math works out to (2 × 4 × 10) ÷ 12 = 6.67 board feet.

Even though the actual milled dimensions of a 2x4 are 1.5 inches by 3.5 inches (which yields about 4.38 board feet of physical wood), suppliers always buy, sell, and price lumber using nominal measurements.

Twenty board feet represents a total wood volume of 2,880 cubic inches (20 times the 144 cubic inches in a single board foot).

To visualize this volume in real-world lumber, 20 board feet is equivalent to:

Single Board: A board 1 inch thick, 12 inches wide, and 20 feet long.
2x4 Lumber: Five 2x4 boards that are each 6 feet long (or three 2x4s that are 10 feet long).
2x6 Lumber: Five 2x6 boards that are each 8 feet long.
1x6 Lumber: Four 1x6 boards that are each 10 feet long.

Any combination of lumber whose dimensions equal (Thickness in inches × Width in inches × Length in feet) ÷ 12 = 20 will equal 20 board feet.

Conclusion

Estimating lumber volume accurately boils down to understanding how board feet work across both raw logs and finished dimensional wood. By measuring the narrow-end diameter and length of a log, you can use industry scales like Doyle, International 1/4-Inch, or Scribner to project usable yield, while standard dimensional lumber relies on nominal formulas based on total volume (144 cubic inches per board foot). Whether you are scaling standing timber for sale or purchasing boards for flooring and decking, always account for practical real-world factors such as kerf loss, milling reductions, and a 10% to 25% waste buffer for fitting to ensure you order or cut the exact amount of wood your project demands.

Read More:

Log Board Foot Calculator | Estimate Yield & Volume