How do I measure the diameter of a log accurately?

For the most accurate result, measure the diameter at the midpoint of the log's length. Since logs are rarely perfectly round, take two measurements at 90 degrees to each other and average them. Avoid measuring at the very ends or at a root flare, as this will skew the result.

Does this calculator account for the taper of the log?

This calculator uses the average diameter to approximate the log as a perfect cylinder, which is a standard method for quick volume estimation. It implicitly accounts for taper by using the midpoint diameter. For highly precise forestry calculations, more complex formulas that treat the log as a frustum (a cone with the tip cut off) are used.

Is the volume of the bark included in this calculation?

Yes, this calculation is based on the outside diameter of the log, so it includes the volume of the bark. The volume of wood fiber inside will be slightly less. The amount of bark can vary from 5% to 15% of the total volume depending on the tree species.

How can I calculate the volume of a log with a hollow center?

You would perform two calculations. First, calculate the total volume of the log using its outside diameter. Second, calculate the volume of the hollow 'missing' cylinder using the diameter of the hollow section. Subtract the volume of the hollow from the total volume of the solid log to get the net volume.

How does log volume relate to board feet?

Log volume is a measure of the total space the log occupies. Board feet is an estimate of the amount of usable, rectangular lumber that can be sawn from that log. One cubic foot of log volume does not equal 12 board feet, because a significant amount of volume is lost to the saw kerf and the rounded slabs cut from the outside of the log. To convert volume to board feet, you need to use a log scaling rule (like Doyle, Scribner, or International).

What is a reasonable accuracy expectation?

For a sound, reasonably straight log measured at its midpoint, cylinder volume is typically within about 5–10% of true solid volume. Badly tapered, flared, or crooked logs drift further, which is why professionals often break long or irregular logs into shorter sections and sum their volumes.

Can I use this for stacked firewood?

Not directly. This measures solid wood volume. Stacked firewood includes air gaps, so you would apply a space factor (often 60–80% depending on how it's split and stacked) to relate solid cubic feet to a cord.

What units does the calculator expect?

Enter diameter in inches and length in feet. Internally the tool converts the radius to feet before applying the cylinder formula, so mixing units (for example, giving the length in inches) will produce a wildly wrong volume. As a scale check, remember the radius is squared: doubling the diameter roughly quadruples the volume of a log of the same length.

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Log & Timber

Log Volume Calculator

Calculate the volume of a log in cubic feet.

Calculating the volume of a log is a fundamental first step for many forestry and woodworking tasks. Whether you're estimating log weight, determining potential board foot yield, or calculating firewood volume, it all starts with knowing the log's cubic footage.

This calculator simplifies the process by treating the log as a perfect cylinder. By providing the average diameter and length, you can get a quick and reliable estimate of its total volume, which is essential for any subsequent calculations regarding the log's value or utility.

Calculator

Enter your measurements and specifications

Log Diameter (inches)

Log Length (feet)

Results

Your calculation results and recommendations

Estimated Log Volume

0.00 ft³

Step-by-Step Instructions & Formula

The volume of a log is calculated using the standard formula for the volume of a cylinder.

Measure Log Dimensions: Measure the average diameter of the log in inches and the total length in feet.
Convert Diameter to Radius in Feet: The calculator first divides the diameter by 2 to get the radius, then divides by 12 to convert the radius from inches to feet.
Apply Volume Formula: It then uses the formula `V = πr²h`, where 'r' is the radius in feet and 'h' is the length in feet.
Volume (ft³) = π × (Radius (ft))² × Length (ft)

Real-World Examples

Example 1: A Standard Sawlog
A log 20 inches in diameter and 16 feet long. Radius = (20 / 2) / 12 = 0.833 ft.
Volume: `π × 0.833² × 16 ≈ 34.9` ft³ of solid wood.

Example 2: A Small Woodlot Pine
A pine 12 inches in diameter and 12 feet long. Radius = 0.5 ft.
Volume: `π × 0.5² × 12 ≈ 9.4` ft³ — roughly a quarter of a face cord of firewood depending on how it's stacked.

Common Mistakes & Troubleshooting

Measuring at the Butt: Taking the diameter at the wide root flare overstates volume. Measure at the log's midpoint.
Feet and Inches Mixed Up: The formula needs radius in feet. Forgetting to divide the inches by 12 inflates the result by a factor of 144.
Using Only One Diameter Reading: Logs are oval. Average two readings at 90° to each other for a fair figure.
Assuming Volume Equals Lumber: Cylinder volume includes bark and round edges you can't turn into square boards.

Expert Insights

"For quick field work I estimate a few logs by cylinder volume, then apply a conversion factor to guess board feet. It's never exact, but it stops me from over-committing equipment to a load that's really bigger — or smaller — than it looks." — Logging Contractor

"If a log is badly tapered or crooked, break it into two shorter sections and volume each one. Two cylinders approximate an irregular shape far better than one long one."

Use Cases

Weight Estimation: Multiply cubic volume by species density to size lifting and hauling gear.
Firewood Planning: Convert standing logs into cords and face cords.
Timber Sales: Give buyers and sellers a common volume baseline before applying a log rule.
Project Sourcing: Judge whether a log holds enough material for a slab, beams, or turning stock.

Glossary of Terms

Volume: The amount of three-dimensional space occupied by an object, measured in cubic units like cubic feet (ft³).
Cylinder: A three-dimensional solid with two parallel circular bases and a curved surface connecting them. Logs are approximated as cylinders for volume calculations.
Log Taper: The natural decrease in a log's diameter from its base to its top. This calculator uses an average diameter to account for taper.

Frequently Asked Questions

Written by

WoodCalc Editorial Team

DIY woodworkers & shop practitioners

Reviewed by

Jordan Vale

Journeyman carpenter & shop-math reviewer

Updated Jan 10, 2026

How we calculate & sources

Formulas follow accepted woodworking practice and cited building-code / industry standards. Results are estimates — always verify against your own material and local code.

Wood Handbook — Wood as an Engineering Material (USDA Forest Service)
International Residential Code (IRC), Span Tables

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Pro Tips

Always double-check your measurements before cutting.
Account for the kerf (the width of the saw blade) in your calculations.
Consider wood movement (expansion and contraction) in your final dimensions.
Buy 10-15% extra material to account for mistakes and waste.