Calculate Board Feet Tree

Estimate standing tree volume or log volume in board feet using standard log rules. This premium calculator lets you compare Doyle, Scribner, and International 1/4 inch estimates, review your assumptions, and visualize volume across rules in a responsive chart.

Board Foot Calculator

How to calculate board feet in a tree

Knowing how to calculate board feet in a tree is one of the most practical skills in forestry, sawmilling, timber marketing, and woodland management. A board foot is a unit of lumber volume equal to a board that is 1 inch thick, 12 inches wide, and 12 inches long. In pure geometric terms, that equals 144 cubic inches. In real timber work, however, standing trees and logs are not converted into board feet with simple geometry alone. Foresters, log buyers, and mill operators generally rely on established log rules that estimate how much sawn lumber can be recovered from a log after accounting for slab loss, taper, kerf, and handling assumptions.

If you want to estimate the value of a standing tree before harvest, compare offers from buyers, plan a small sawmill job, or learn whether a tree is worth cutting for lumber, board foot estimation gives you a common language for volume. The calculator above helps with two practical use cases. First, it estimates board feet for a standing tree from diameter at breast height and merchantable height. Second, it computes board feet more directly when you already know the small end diameter inside bark and the log length. Both methods are useful, but the log method is more precise because it uses dimensions closer to the actual point where lumber recovery is measured.

What measurements matter most

To calculate board feet in a tree or log, the most important measurements are diameter and merchantable length. For a standing tree, diameter at breast height, usually called DBH, is measured 4.5 feet above the ground on the uphill side. Merchantable height is the usable stem length from stump height to the point where the stem becomes too small, crooked, rotten, or defective to produce marketable logs. For a cut log, the more relevant input is small end diameter inside bark because that measurement is directly used in most board foot rules.

• DBH: Outside bark stem diameter measured at 4.5 feet above ground.
• Merchantable height: Usable log length from stump to merchantable top.
• Small end diameter inside bark: The narrow end measurement used in common scaling rules.
• Log length: Usually measured in 8 foot or 16 foot increments, though mills may specify trim allowances.
• Log rule: The formula used to convert dimensions into board feet.

The three most common board foot log rules

In the United States, the three rules most commonly discussed are Doyle, Scribner, and International 1/4 inch. Each rule estimates lumber yield differently, so the same log can have three different board foot values depending on which rule is used. This is why it is essential to know the rule being used when you compare stumpage prices, timber bids, or sawlog estimates.

Doyle rule

The Doyle rule is simple and widely used in parts of the eastern and southern United States. A common formula for a straight log is:

Doyle board feet = ((D – 4)² × L) / 16, where D is small end diameter inside bark in inches and L is length in feet.

Doyle tends to underestimate small logs because it assumes a relatively large slab loss. As log diameters get larger, Doyle estimates become less conservative relative to actual recovery. This can have a major effect on pricing. A woodland owner who thinks in Doyle and a sawmill that thinks in International can see very different volumes on the same load.

Scribner rule

The Scribner rule is based on diagramming boards inside a round log. A common modern formula approximation is:

Scribner board feet = ((0.79 × D²) – (2 × D) – 4) × (L / 16).

Scribner generally estimates more volume than Doyle for smaller logs, though it still does not perfectly reflect modern milling efficiency. It remains popular in many timber markets because of long regional tradition and buyer familiarity.

International 1/4 inch rule

The International 1/4 inch rule is often viewed as the most technically realistic of the three because it accounts more directly for taper and a 1/4 inch saw kerf. A common formula for a straight log is:

International board feet = (0.199 × D² – 0.642 × D – 1) × (L / 4).

For many sizes, International 1/4 inch produces a higher estimate than Doyle and often a somewhat different estimate than Scribner. In educational settings, this rule is frequently used to illustrate a closer approximation of actual sawn yield, especially when compared with older rules designed around historic milling conditions.

Standing tree estimates versus actual log scaling

Standing tree board foot estimation is useful, but it is still an estimate. A standing tree has bark thickness, taper, sweep, knot clusters, hidden decay, butt flare, crook, and species-specific form characteristics that affect actual recoverable lumber. A standing tree calculator usually takes DBH and merchantable height, applies a taper assumption, and then converts the estimated merchantable stem into one or more logs. This can be surprisingly helpful for planning, but it will never replace a full cruise or actual log scaling after felling.

1. Standing tree method: Fast and practical for woodland planning, thinning, and rough valuation.
2. Scaled log method: Better for sale settlement, sawmill intake, and more precise yield estimates.
3. Sawn lumber tally: Best for knowing what was actually produced after milling.

Log size example	Doyle bf	Scribner bf	International 1/4 inch bf
12 inch diameter x 16 foot log	64	86	101
16 inch diameter x 16 foot log	144	166	190
20 inch diameter x 16 foot log	256	272	304
24 inch diameter x 16 foot log	400	429	467

The table above uses standard rule formulas and shows why rule selection matters. For a 12 inch by 16 foot log, Doyle estimates only 64 board feet while International estimates about 101 board feet. That is a difference of almost 58 percent. At larger diameters, the spread narrows in percentage terms, but the absolute volume difference can still be substantial. This is exactly why landowners should always ask what scale rule a buyer is using and whether deductions for defects are taken before or after scaling.

How to estimate a standing tree more accurately

If you are measuring a tree before it is cut, accuracy improves when you make the merchantable height realistic and avoid treating the stem as a perfect cylinder. The upper stem narrows quickly, and trees vary significantly by species and site quality. A straight, well-pruned hardwood with a clear bole will scale differently from a limby open-grown tree of the same DBH. Good practice means using a log scale stick, Biltmore stick, clinometer, laser rangefinder, or cruising app to confirm dimensions rather than guessing from the ground.

• Measure DBH carefully at the correct height and avoid bark ridges or deformities.
• Count only merchantable stem length, not total height.
• Adjust for poor form, crook, sweep, butt rot, seam, and excessive limb knots.
• Use the same rule that your local market uses when comparing values.
• Remember that standing estimates should be treated as planning numbers, not final settlement numbers.

Common reasons estimates go wrong

Many board foot estimates are off because of one or more avoidable mistakes. The biggest issue is confusing diameter outside bark with small end diameter inside bark. Another common problem is counting too much merchantable height, especially in trees that lose quality above the first log or two. Some people also compare board foot values across buyers without noticing that one buyer uses Doyle and another uses Scribner or International. Finally, hidden defects such as internal decay or shake can dramatically reduce the recoverable volume even when the exterior appears sound.

Factor	Effect on board foot estimate	Practical impact
1 inch diameter measurement error	Often changes scale by 8 percent to 20 percent depending on size class	Can materially change value per log
Using wrong scale rule	Can change estimate by 10 percent to 50 percent on small and medium logs	Makes bid comparison unreliable
Overstating merchantable height by one 16 foot log	Directly adds a full extra log to the estimate	Common source of optimistic standing timber estimates
Ignoring defect	May reduce scale or value substantially	Important for veneer, grade sawlogs, and old trees

When to use board feet and when to use cubic volume

Board feet are excellent for sawtimber because they align with how lumber yield and many stumpage markets are discussed. However, board feet are less useful for pulpwood, biomass, firewood, and some inventory applications where cubic feet or cords may be more appropriate. Cubic volume reflects the actual solid wood content of the stem, while board foot rules estimate lumber output under assumed sawing conditions. If your goal is forest inventory, growth modeling, carbon estimation, or biomass accounting, cubic measures may be better. If your goal is selling sawlogs, planning milling, or checking a timber bid, board feet are often the right language.

Best practices before selling a tree or timber stand

If you are trying to value a high quality tree or a group of trees, the smartest move is to combine your own rough estimate with professional input. A consulting forester can mark timber, estimate merchantable volume by species and product, solicit bids, and help interpret local market conditions. Even a simple cruise can reveal whether your stand should be sold now, improved with a thinning, or held longer for more growth and value.

1. Measure representative trees rather than relying on a single average.
2. Separate products by quality class if possible, such as veneer, sawlog, and pulp.
3. Ask every buyer what log rule and defect deductions they use.
4. Request written bid terms, including payment method and harvest conditions.
5. Consider professional forestry assistance for high value sales.

Authoritative forestry references

Useful references for timber measurement, scaling, and woodland management: U.S. Forest Service, Penn State Extension, University of Minnesota Extension.

Final takeaway

To calculate board feet in a tree, start with the best measurements you can get, choose the correct rule for your region or buyer, and understand that a standing tree estimate is only a planning tool until the logs are actually scaled. If you know log dimensions, use them directly because the result will be more reliable. If you only know DBH and merchantable height, a standing estimate is still highly useful for rough valuation, harvest planning, and comparing trees across a woodlot. The calculator on this page makes both workflows faster by showing your primary result and comparing the three major rules side by side in a chart.

This calculator provides educational and planning estimates. Actual sawtimber scale and value can vary with species, taper, defect, trim allowance, local log rule practice, and mill specifications.