Other Calculator
Log Weight Calculator
Quickly estimate the weight and volume of round wooden logs. This utility calculates the physical volume of a log in cubic feet based on its length and taper, then applies the specific density profile of your selected wood species across different moisture conditions (freshly cut green, air-dried, or kiln-dried).
Log Weight Calculator
Estimate log weight by dimensions and wood species
Results
Enter log dimensions above and click Calculate
How Does Log Weight Calculation Work?
In logging, arboriculture, forestry, and woodworking, estimating log weight is vital for transport safety, load capacity checks, and material handling. Because logs are natural materials that taper from the wide butt end to the narrow top end, weight calculation requires modeling the log as a cylinder using its average diameter.
A Log Weight Calculator uses three main variables: the length, the diameters of both ends (to determine the average midpoint thickness), and the density of the wood species. Because wood is porous and holds moisture, the weight varies heavily depending on whether the timber is green (wet) or has been seasoned.
Mathematical Formulas for Log Weight
We treat the log as a cylinder. The calculation comprises three mathematical stages:
Wood Species Density Reference (lbs/ft³)
The table below lists the average weight densities in pounds per cubic foot (lbs/ft³) for the preset wood species included in this calculator:
| Wood Species | Green (Fresh) | Air-Dried | Kiln-Dried |
|---|---|---|---|
| Pine (Southern Yellow) | 52.34 | 36.00 | 34.00 |
| Oak (Red/White) | 62.10 | 47.00 | 44.00 |
| Douglas Fir | 48.00 | 45.36 | 34.00 |
| Maple | 60.00 | 44.00 | 42.00 |
| Cedar | 32.00 | 23.00 | 21.00 |
| Walnut | 58.00 | 38.00 | 35.00 |
Key Features of Our Log Weight Calculator
Step-by-Step Log Weight Examples
Example Calculation 1 — Pine Log (Green)
Length: 16 feet, Large End: 20 inches, Small End: 16 inches, Species: Southern Yellow Pine (Green)
Average Diameter = (20 in + 16 in) ÷ 2 = 18.00 inches
Radius in Feet = 18.00 in ÷ 24 = 0.75 ft
Volume = π × (0.75 ft)² × 16 ft = π × 0.5625 × 16 = 28.274 cubic feet
Density (Green Southern Yellow Pine) = 52.34 lbs/ft³
Estimated Weight = 28.274 ft³ × 52.34 lbs/ft³ = 1,480 lbs (approx. 671 kg)
Example Calculation 2 — Oak Log (Green)
Length: 12 feet, Large End: 24 inches, Small End: 22 inches, Species: Red Oak (Green)
Average Diameter = (24 in + 22 in) ÷ 2 = 23.00 inches
Radius in Feet = 23.00 in ÷ 24 = 0.9583 ft
Volume = π × (0.9583 ft)² × 12 ft = 34.623 cubic feet
Density (Green Red Oak) = 62.10 lbs/ft³
Estimated Weight = 34.623 ft³ × 62.10 lbs/ft³ = 2,150 lbs (approx. 975 kg)
Example Calculation 3 — Small Dry Log
Length: 8 feet, Diameter: 12 inches (both ends), Species: Douglas Fir (Air-Dried)
Average Diameter = (12 in + 12 in) ÷ 2 = 12.00 inches
Radius in Feet = 12.00 in ÷ 24 = 0.50 ft
Volume = π × (0.50 ft)² × 8 ft = 6.283 cubic feet
Density (Air-Dried Douglas Fir) = 45.36 lbs/ft³
Estimated Weight = 6.283 ft³ × 45.36 lbs/ft³ = 285 lbs (approx. 129 kg)
Key Variables in Wood Weight
- Mid-point vs. End Diameters: Because logs are irregular, taking the average of the narrow (small end) and wide (butt/large end) diameters yields a much more accurate volume estimate than using just one measurement.
- Green Weight Margin of Safety: Green logs vary widely in weight. When rigging or choosing lifting equipment, always use the heaviest green density estimate to prevent overloading.
- Grain and Density Variation: The growth ring density, sapwood proportion, and mineral content of the soil can cause wood density to vary up to 10%–15% from the nominal average species weights.
Frequently Asked Questions
- How does the Log Weight Calculator work?
- The Log Weight Calculator estimates the weight of a round log by calculating its total volume in cubic feet based on its length and average diameter. It then multiplies this volume by the density (pounds per cubic foot) of the selected wood species at its current moisture condition (Green, Air-Dried, or Kiln-Dried).
- What formula is used to calculate log volume?
- We treat the round log as a cylinder. The volume is calculated as: Volume (cubic feet) = π × (Average Diameter in inches / 24)² × Length (feet). The average diameter is the average of the large end and small end diameters of the log.
- Why does moisture condition affect wood weight?
- Freshly cut "green" logs contain a high amount of water within their cell walls and cavities, sometimes exceeding 100% moisture content (where water weighs more than dry wood). As wood dries (air-dried or kiln-dried), this water evaporates, causing the wood to become significantly lighter and slightly smaller due to shrinkage.
- What are the moisture conditions (Green vs. Air-Dried vs. Kiln-Dried)?
- Green wood is freshly harvested timber with high moisture levels. Air-Dried wood has dried naturally in the open air, typically reaching 15%–20% moisture content. Kiln-Dried wood is processed in a heated chamber to bring moisture content down to 6%–12%, which is the lightest state.
- How do you find the average diameter of a tapered log?
- For tapered logs, standard scaling guidelines use the average of the two end diameters: Average Diameter = (Large End Diameter + Small End Diameter) / 2. This represents the midpoint diameter for the volumetric calculations.
- How accurate is this weight calculator?
- This calculator provides a highly accurate estimate based on standard species density averages. However, actual log weights can vary due to factors like regional growth rates, sapwood-to-heartwood ratios, bark thickness, and exact moisture levels. For commercial hauling or rigging, always apply a safety factor.