Board Feet Calculator for Logs
Estimate log volume quickly using common log scaling rules. Enter the small-end diameter, log length, bark deduction, quantity, and your preferred rule to calculate board feet and compare Doyle, Scribner, and International 1/4-inch estimates in one premium tool.
Interactive Log Scale Calculator
This calculator is designed for sawlog estimation. Results are based on standard rule formulas and are best used for planning, bidding, and rough yield comparisons.
If you measured outside bark, use the bark deduction field below.
Many mills scale logs in standard 8, 10, 12, 14, 16, 18, or 20 foot lengths.
Set to 0 if your diameter is already estimated inside bark.
Use this to estimate total board feet for a group of similar logs.
Different regions and buyers may rely on different scale rules.
Rounding changes display only and does not alter the chart comparison.
Your results will appear here
Enter your values and click Calculate Board Feet to estimate the log volume and compare rule-based outcomes.
Expert guide to using a board feet calculator for logs
A board feet calculator for logs helps landowners, foresters, sawyers, log buyers, and woodlot managers estimate how much lumber a log may yield before it reaches the mill. At its core, the calculator converts field measurements into a standardized volume estimate called board feet. That estimate is useful for timber cruising, pricing, inventory planning, portable sawmill scheduling, harvest forecasting, and rough comparisons among logs of different size classes. If you have ever asked how many board feet are in a 16-foot oak log or why one mill quotes a different volume than another, the answer usually lies in the scaling rule being used and in how the log was measured.
The term board foot is a lumber measure rather than a direct standing-tree measure. One board foot equals 144 cubic inches, which is the same as a piece of wood 12 inches by 12 inches by 1 inch. In pure geometry, one cubic foot equals 1,728 cubic inches, so there are exactly 12 board feet in one cubic foot of solid wood. However, logs are round, they taper, they contain bark, and lumber production creates slabs, saw kerf, trim loss, and defects. That is why the industry relies on scale rules such as Doyle, Scribner, and International 1/4-inch instead of using a simple cubic formula alone.
Why a log board foot estimate matters
When logs are bought and sold, a common language is essential. Board foot scaling creates that common language. It allows a landowner to compare bids, a logger to estimate truck payload value, and a sawyer to project output from a custom milling job. In timber sales, a few inches of diameter or a different scale rule can shift volume materially, especially across multiple loads. A calculator saves time and reduces arithmetic errors in the field while also making it easier to compare the effect of each scaling rule on the same log.
- Estimate log value before sale or transport.
- Compare buyer quotes that use different scale rules.
- Plan milling jobs and expected lumber output.
- Organize inventory by species, tract, or harvest unit.
- Understand why smaller logs often scale differently than larger logs.
The three most common rules: Doyle, Scribner, and International 1/4-inch
Not all board foot rules are created equal. Each one was designed in a different era with different assumptions about saw kerf and milling practices. As a result, the same log may produce three different estimates depending on which rule is applied. This is one of the most important concepts to understand when using any board feet calculator for logs.
- Doyle rule: Common in parts of the eastern and southern United States. It is simple and widely recognized, but it generally underestimates volume in smaller diameter logs. For large logs, Doyle can align more closely with actual mill output in some regional situations.
- Scribner rule: Another traditional scale based on diagrammatic assumptions. It often produces higher figures than Doyle for small and medium logs and remains common in some markets.
- International 1/4-inch rule: Often considered the most technically balanced of the three because it better reflects taper and a realistic saw kerf assumption. Many foresters prefer it for planning because it behaves more consistently across log diameters.
Because buyers and mills can use different rules, there is no single universal board foot answer for every log. The correct estimate depends on your market context. That is why this calculator not only gives a primary result based on your selected rule, but also compares all three rules side by side in the chart.
How to measure a log correctly
Good measurements lead to useful estimates. Most scaling systems start with the small-end diameter of the log, usually inside bark, and the merchantable log length. If you measure outside bark, bark thickness should be deducted. Bark deduction varies by species, age, and growing conditions, which is why a flexible percentage field can be helpful in a general-purpose calculator.
- Diameter: Measure the small end of the log. If the log is not perfectly round, average the narrow and wide dimensions.
- Inside bark: If possible, estimate the wood diameter without bark. If that is not practical, apply a bark deduction percentage.
- Length: Measure the usable merchantable length, typically in feet. Add trim only if your local scaling practice requires it.
- Quantity: If several logs are similar in size, multiply by quantity for a quick batch estimate.
| Reference fact | Value | Why it matters in scaling |
|---|---|---|
| 1 board foot | 144 cubic inches | Base unit for estimating sawn lumber volume |
| 1 cubic foot | 1,728 cubic inches | Useful for checking dimensional consistency |
| Board feet in 1 cubic foot of solid wood | 12 board feet | Quick conversion before saw kerf and slab losses |
| Common sawlog lengths | 8 to 20 feet | Most calculators and mills work best with standard lengths |
Sample comparison: the same log can scale very differently
To see why rule selection matters, compare several common log sizes below. These figures are calculated from standard approximate rule formulas like the ones used in this page. They are not guaranteed mill tallies, but they do show why one buyer may quote noticeably more or less volume than another when the scale rule changes.
| Small-end diameter | Length | Doyle | Scribner | International 1/4-inch |
|---|---|---|---|---|
| 14 inches | 12 feet | 75 bf | 95 bf | 104 bf |
| 16 inches | 16 feet | 144 bf | 170 bf | 180 bf |
| 20 inches | 16 feet | 256 bf | 272 bf | 263 bf |
| 24 inches | 12 feet | 300 bf | 314 bf | 311 bf |
The table highlights a classic pattern: Doyle is usually lower on smaller logs, then narrows the gap as diameter increases. International 1/4-inch often provides the most even progression across sizes. Scribner frequently falls between the two, though exact relationships vary with diameter and length.
What this calculator can and cannot tell you
A board feet calculator for logs is a practical estimating tool, not a full mill accounting system. It helps you compare log volume under standardized rules, but it cannot perfectly predict sawn lumber recovery. Actual yield depends on species, taper, sweep, crook, butt flare, knots, rot, stain, log straightness, trim allowance, saw kerf, mill setup, target lumber dimensions, and operator decisions. Two logs with identical measurements can still produce different lumber outcomes if one contains internal defect or if the sawyer is cutting for grade versus maximum volume.
When to use each rule
If you are a landowner preparing for a timber sale, ask buyers and consulting foresters which rule the local market uses. In some areas, Doyle remains the default because that is how mills and procurement systems have historically operated. If you are comparing productivity or trying to normalize estimates across a range of diameters, International 1/4-inch may be more useful analytically. If you work with historic stumpage reports or local custom mills, Scribner may still be relevant. The point is not that one rule is always right and the others are wrong. The point is that the same physical log may be valued through different conventions.
Practical tips for better board foot estimates
- Measure the small end carefully. A 1 inch diameter difference can change value substantially over many logs.
- Use realistic bark deduction when measuring outside bark. Thick-barked species can otherwise be overstated.
- Separate logs by similar diameter and length classes before estimating quantity totals.
- Record species and apparent defect notes. Volume alone does not determine grade or price.
- Verify whether the buyer scales gross or net and how defect deductions are handled.
- Use the comparison chart to understand how sensitive your estimate is to the chosen rule.
Authority and reference sources
If you want to study log scaling in more depth, consult forestry and extension resources from public institutions. Useful references include the USDA Forest Service, timber measurement material from Penn State Extension, and wood products or forest measurements information from land-grant universities such as Oklahoma State University Extension. These sources provide context on merchantable volume, scaling conventions, log grades, and harvesting decisions.
How professionals use board foot estimates in the field
In real forestry operations, volume estimates are rarely isolated. A consultant may combine board foot estimates with basal area, stocking, species composition, access limitations, trucking distance, and current market conditions. A custom sawyer may use board foot estimates to quote milling rates, determine blade needs, and schedule drying space. A logger may use them to rank loads by expected revenue. In every one of those use cases, speed matters. A reliable calculator streamlines decisions while maintaining a transparent method that can be reviewed later.
Board feet also help bridge communication between professionals and property owners. Many landowners know the number of trees on a tract but have little sense of how much usable lumber those trees represent once bucked into logs. A board foot estimate brings the conversation down to merchantable product. It is not perfect, but it is highly practical, especially when paired with sound advice from a forester and with local market knowledge.
Bottom line
A board feet calculator for logs gives you a fast, standardized way to estimate potential lumber volume from measured logs. The most important variables are small-end diameter, length, bark treatment, quantity, and scale rule. If you understand those inputs, you can use the calculator to compare logs more confidently, discuss pricing more intelligently, and avoid confusion when one source reports a different volume than another. For decision-making in the real world, always pair the estimate with local scaling practices, defect assessment, and the exact purchasing terms used by the mill or buyer.