Article — Log Weight Calculator
Log Weight Calculator: Round Timber Weight by Species and Moisture
A green pine log 16 inches in diameter and 10 feet long weighs about 660 pounds (300 kg) at 80% moisture content — the average green-MC state for freshly milled softwood. The math: cylinder volume = π × 0.667² × 10 = 13.96 ft³; green density = 0.42 (specific gravity) × 62.4 (water density) × 1.8 (MC factor) = 47.2 lb/ft³; weight = 13.96 × 47.2 = 659 lb. Red oak the same size weighs 1,168 lb (530 kg) because oak's specific gravity of 0.62 makes it 47% denser than pine.
This calculator uses specific gravity references for nine common North American species and computes both metric and imperial weight, plus log-rule scale (Doyle and Scribner) for sawlog applications. The cylinder volume formula is accurate to within 5% of the Smalian formula for logs under 16 feet — for very tapered or long logs, average the butt and tip diameters before entering.
How the log weight calculator works
Enter the average diameter (midway between butt and tip, or the average of the two ends), the log length, the species (which sets specific gravity), and the moisture content. The calculator computes cylinder volume as π × (D/2)² × L, multiplies specific gravity by 62.4 lb/ft³ to get oven-dry density, then applies a moisture-content multiplier of (1 + MC/100) to get the actual green density.
The output shows weight in pounds, kilograms, US short tons, and metric tonnes. It also gives the volume in cubic feet and cubic meters, plus three different board-foot estimates: the simple cubic-foot × 12 conversion (for rough volume comparisons), the Doyle log rule (eastern US hardwood standard), and the Scribner Decimal C rule (Pacific Northwest and federal timber sales). Different markets quote in different log rules, so all three are shown for comparison.
Log weight by species
Specific gravity is the dominant variable. Western red cedar at SG 0.32 produces a green density around 33 lb/ft³; the same diameter and length log of white oak at SG 0.68 produces 70 lb/ft³ — more than twice as heavy. Common North American species cluster as follows: softwoods 0.30 to 0.45 (cedar, pine, spruce, hemlock, fir), medium hardwoods 0.50 to 0.55 (walnut, ash, birch), dense hardwoods 0.58 to 0.68 (maple, oak, hickory), and tropical hardwoods 0.70+ (ipe, lignum vitae).
Within a species, SG varies by growing region and stem position. Slow-grown trees from cold climates produce denser wood than fast-grown plantation trees of the same species. Heartwood is typically 5 to 10% denser than sapwood. Old-growth Douglas fir averages SG 0.50 versus 0.42 for plantation second-growth. For high-precision applications (engineered timber, structural species grading), use the actual SG measured from a sample rather than the species average.
Cedar ~620 lbSpruce / Hemlock ~750 lbPine ~790 lbDouglas Fir ~820 lbRed Oak ~1,170 lbWhite Oak / Hickory ~1,280 lbGreen vs seasoned log weight
Freshly cut logs are heavy because they carry water — typically 60 to 100% of the oven-dry wood weight in additional water content. A green oak log at 70% MC contains 1.70 times its oven-dry weight in total mass. As the log dries outdoors, free water in the cell cavities evaporates first (above the 30% fiber saturation point), then bound water leaves the cell walls more slowly. The weight loss is approximately 1% MC per day for the first month outdoors in warm dry weather, slowing to 1% per week below 30% MC.
Seasoned firewood at 20% MC has lost roughly 30 to 40% of its green weight. A 90-pound green oak round becomes a 60-pound seasoned round after 12 months split and stacked. The transport implication: hauling green firewood requires roughly double the trips compared to hauling seasoned wood for the same usable energy content. Loggers and millers do most heavy hauling within 30 days of cutting, before seasoning starts to soften the bark and make handling messier.
Log weight for firewood
The traditional firewood unit is the cord: a stack 4 feet wide, 4 feet tall, and 8 feet long, totaling 128 cubic feet of stacked wood. After accounting for air gaps between split pieces (typically 20 to 30% of stack volume), a cord contains roughly 80 to 90 cubic feet of actual wood substance. Green oak cord weight: 4,200 to 5,000 lb. Seasoned oak (20% MC) cord: 3,500 to 4,000 lb. Pine green cord: 2,800 to 3,400 lb; seasoned: 2,200 to 2,800 lb.
For trailer planning, a single-axle utility trailer rated for 3,500 lb gross can carry about three-quarters of a seasoned oak cord (or one full cord of seasoned pine). A 5,000 lb tandem-axle trailer fits one full cord of seasoned hardwood with some safety margin, or three-quarters of a cord of green oak. Always check the trailer's GVWR sticker, not the advertised "carrying capacity" — the GVWR includes the trailer's own weight, often 800 to 1,200 lb.
Doyle and Scribner log rules
Log rules estimate the yield in board feet of lumber from a log of given diameter and length. The Doyle rule uses (D − 4)² / 16 × L, where D is the small-end diameter in inches and L is the length in feet. It is the standard in the eastern US hardwood market, especially Appalachian region oak sales. Doyle is conservative on small logs — it underestimates yield by 25 to 50% for logs under 14 inches and is consequently favorable to buyers and unfavorable to sellers.
The Scribner Decimal C rule is more accurate for logs over 14 inches and is the US Forest Service standard for federal timber sale appraisals. Its formula is more complex but produces consistent yields across the diameter range. The Pacific Northwest and Rocky Mountain markets use Scribner exclusively. International Quarter-Inch (the third major rule) is the most theoretically accurate but rarely used commercially because its values do not match either traditional market expectations.
The Doyle log rule was published by Edward Doyle in 1825 and assumes a uniform saw kerf of 5/16 inch — much wider than modern thin-kerf bandsaw blades, which lose only 1/16 inch per cut. This is why Doyle consistently underestimates modern sawmill yield: the formula was calibrated for circular saws of the early 1800s. The rule survives because state forestry agencies, hardwood lumber brokers, and stumpage contracts all reference it by name, and changing standards would require renegotiating thousands of long-term timber contracts.
Log weight for truck loads
Logging trucks in North America typically carry 60,000 to 80,000 lb gross vehicle weight (GVW), with about 35,000 to 50,000 lb of payload after subtracting the empty truck weight. A standard 9-axle log truck (3-axle tractor + 6-axle log trailer) can carry roughly 25 green oak logs at 18 inches × 16 feet each (2,400 lb per log × 20 = 48,000 lb total) — the legal limit on most state highways before special permits.
For homeowner planning of single-log retrievals, a half-ton pickup (1,500 lb payload) handles one log up to about 16 inches diameter × 10 feet for softwood, or 14 inches × 10 feet for hardwood. A one-ton pickup (3,000+ lb payload) doubles those limits. Beyond that, a trailer is mandatory. Always account for the chains and binders (50 to 100 lb of additional gear), and remember that a wet log shifts its center of gravity slightly forward of geometric center, putting more load on the front axles.
- Cylinder volume formula = π × (D/2)² × L
- Green pine density = 45 lb/ft³ at 80% MC
- Green oak density = 64 lb/ft³ at 75% MC
- One cord = 128 ft³ stacked, 80-90 ft³ actual wood
- Seasoned firewood = below 20% MC, ready to burn
- Doyle rule = (D-4)² / 16 × L (D in inches, L in feet)
- Log truck GVW = 60,000 to 80,000 lb in most US states
- Air-dry rate = ~1% MC per day for first month outdoors
Common log weight mistakes
The first mistake is using kiln-dry density values for green logs — undersizing the calculation by 40 to 80%. The second is measuring only the butt diameter on a tapered log, ignoring that the average diameter is significantly smaller. The third is forgetting bark weight: bark adds 8 to 15% to the green weight of most species and is included in commercial scale measurements but not in calculator volumes computed from diameter inside bark.
A "small" 12-inch pine log 16 ft long weighs about 700 lb green — more than enough to crush a foot or trap a leg if it rolls during loading. Always use cant hooks, peavies, or log tongs to roll logs onto trailers; never use bare hands or feet. For logs over 16 inches diameter, a winch or skidder is mandatory. Underestimating log weight is the most common cause of logging-related back injuries among homeowners and small-scale operators.
The fourth mistake is mixing log rules: a quote in "BF" without specifying Doyle, Scribner, or International gives different yield estimates on the same log. The fifth is failing to subtract obvious defects (large knots, splits, rot pockets) from the gross volume before pricing — sawmills will deduct for these on receipt. The sixth is ignoring the small-end vs large-end measurement convention: Doyle and Scribner both use the small-end diameter inside bark, not the average or butt diameter.
For accurate log scaling on a small portable mill, measure the small-end diameter inside bark to the nearest inch (rounding down), record the length to the nearest foot (rounding down), then look up the Scribner BF in a published table or use the calculator. Apply a 10 to 15% defect deduction for ordinary clear-grade logs, 25 to 40% for visible knots or splits. The resulting volume is what your mill should actually yield in usable lumber after surfacing.