Log Weight Calculator
Whether you’re a lumber mill operator estimating truckload weights, a woodworker calculating material costs, or a logger assessing a timber stand, knowing the weight of logs is essential. A log’s weight affects everything from transportation costs and equipment requirements to the price you pay for lumber and the structural calculations for timber-framed buildings. But estimating log weight isn’t straightforward, it depends on the species, moisture content, and dimensions, all of which can vary significantly.
This log weight calculator takes the guesswork out of estimating wood weight. Enter the log dimensions, shape, species, and moisture content, the tool computes the volume in board feet and cubic feet, then calculates the weight in pounds and kilograms. It also provides cost estimates based on price per board foot, with a waste factor for added accuracy. Whether you’re a professional in the forestry industry, a hobbyist woodworker, or a homeowner planning a timber project, this calculator delivers instant, accurate results. All calculations run locally in your browser, keeping your data private.
How to Use the Log Weight Calculator
Select the log shape: Round or Rectangular to match your lumber profile.
For round logs, enter the diameter. For rectangular, enter the width and height.
Enter the log length, the total length of the piece.
Choose the wood species from the dropdown the density updates automatically based on the selected species.
Adjust the moisture content percentage 15% is typical for kiln-dried lumber; green logs can be 30% or higher.
Enter the price per board foot and the number of logs to get a complete cost estimate.
Set a waste factor to account for cuts, defects, and breakage.
Review the summary or switch to the detailed breakdown tab for a full component list.
How the Log Weight Calculator Formula Works
The calculator determines the volume of the log based on its shape and dimensions, then converts the volume to weight using the wood’s density adjusted for moisture content. The calculations follow standard forestry and lumber industry practices.
Formula: Volume = Shape-specific calculation
For round logs: Volume = π × (diameter/2)² × length
For rectangular logs: Volume = width × height × length
All dimensions are converted to inches before calculation, with volume computed in cubic inches.
Formula: Volume (cubic feet) = Volume (cubic inches) / 1728
There are 1,728 cubic inches in one cubic foot.
Formula: Volume (board feet) = Volume (cubic inches) / 144
One board foot equals 144 cubic inches (12 inches × 12 inches × 1 inch).
Formula: Adjusted Density = Base Density × (1 + (Moisture Content − 12) × 0.004)
Wood density increases with moisture content above 12%. This adjustment provides a more accurate weight estimate for logs with different moisture levels.
Formula: Weight = Volume (cubic feet) × Adjusted Density
Weight is calculated in pounds using the adjusted density in pounds per cubic foot.
Formula: Total Cost = Volume (board feet) × Price per Board Foot × Quantity
The cost is based on board feet — the standard unit for lumber pricing.
Worked Example: Estimating a White Oak Log
Consider a white oak log with a 12-inch diameter, 16 feet in length, at 15% moisture content. The density of white oak at 12% MC is 47 lbs/ft³. The woodworker wants to know the weight and cost of the log.
Step 1: Convert dimensions to inches
Step 2: Calculate volume for a round log
Radius = 12/2 = 6 in
Volume = π × 6² × 192 = 3.1416 × 36 × 192 = 21,714.7 in³
Volume (ft³) = 21,714.7 / 1728 = 12.57 ft³
Volume (BF) = 21,714.7 / 144 = 150.8 BF
Step 3: Adjust density for moisture content
Step 4: Calculate weight
Step 5: Calculate cost
Interpretation: A 16-foot white oak log with a 12-inch diameter weighs approximately 598 lbs and has a lumber value of about $377 at $2.50 per board foot. This estimate helps the woodworker plan transportation and budget for the material.