Log Weight Calculator
Estimate green wood volume and weight from species density, dimensions, and quantity.
Wood specifications
Weight results
Calculation breakdown
| Measure | Per piece | Total |
|---|---|---|
| Volume | 13.75 ft³ | 41.24 ft³ |
| Weight | 536.2 lb | 1,608.6 lb |
| Weight | 243.2 kg | 729.6 kg |
The estimate uses geometric volume multiplied by the selected green density. Irregularity, bark, decay, taper, and moisture variation can make actual scale weight differ.
How to use this log weight calculator
What this calculator does
This calculator estimates the volume and green weight of a round log or a rectangular board or timber. It is useful for early-stage handling, transport, lifting, purchasing, and material-planning checks when a certified scale reading is not yet available. The result is an engineering estimate, not a load rating for a truck, crane, sling, trailer, floor, or structure. Real pieces vary because wood density changes with species, moisture, growth conditions, bark, voids, and decay. The USDA Forest Service explains these relationships in its wood moisture and physical-properties chapter.
When to use it
Use the estimate to compare logs before moving them, plan a preliminary hauling load, check whether shop equipment has enough nominal capacity, or convert field dimensions into a purchase or inventory estimate. For safety-critical lifting or transport, confirm the result with actual weighing and the equipment manufacturer's rated-capacity information.
How to calculate
- The calculator opens with a complete Douglas-fir example and an immediately available XLSX export.
- Choose Shape. For a log, enter the two end diameters and length. For a board, enter width, thickness, and length.
- Choose Species or select Custom density and enter a measured or documented Density.
- Enter Quantity. Read total weight, weight per piece, volume, and the breakdown table. Results update as you type.
- Select Download Excel to export the current validated inputs and outputs. Reset clears the demonstration values and results; export remains disabled until a complete valid state is entered again.
Input guide
Shape is required and selects either Huber-style round-log geometry or rectangular-prism geometry. Species supplies a representative green density in pounds per cubic foot. Choosing a species updates Density; selecting Custom density lets you type a positive decimal such as 47.5. Do not treat a species value as a guaranteed property of every tree. Smaller-end diameter and Larger-end diameter are required for logs, accept positive inches such as 16 and 20, and are averaged to estimate the mid-section diameter. Reversing the two ends does not change the estimate, but entering circumference instead of diameter causes a large error. Board width and Board thickness are required only for rectangular pieces and accept positive inches, for example 10 and 2. Length is required in feet and may be decimal, such as 7.5. Quantity is a required whole number from 1 to 100,000. Higher density, dimensions, length, or quantity increase the result proportionally, while diameter affects round-log weight approximately with the square of the averaged diameter.
Output guide
Total weight is the estimated combined green weight in pounds. Weight per piece is the estimate for one piece. Volume per piece and Total volume are cubic-foot geometric volumes. Mid-section diameter appears for logs and is the average of the two end diameters; for boards it is shown as not applicable. The breakdown table repeats volume and weight per piece and for the full quantity, and also converts pounds to kilograms. A zero result is not shown for missing data because a zero-size piece is not meaningful here. High values should trigger a careful review of units and handling capacity.
Worked example
The startup example uses Douglas fir at 39 lb/ft³, a 16-inch smaller end, a 20-inch larger end, a 7-foot length, and 3 pieces. The mid-section diameter is (16 + 20) ÷ 2 = 18 inches, or 1.5 feet. Huber's formula gives 7 × π × 1.5² ÷ 4 = about 12.37 ft³ per piece. Multiplying by 39 lb/ft³ gives about 482.5 lb per piece, and three pieces weigh about 1,447.4 lb. The displayed and exported values use the same unrounded model.
Formula and practical interpretation
Round log: volume = length × π × mid-diameter² ÷ 4. Board: volume = width × thickness × length. Weight = volume × density.
Huber's method treats the cross-section at the log's midpoint as representative of the full length. It is straightforward and useful for field estimates, but highly tapered or irregular logs may need a more detailed scaling method. The USDA Forest Service has published research on estimating log weights from green density, while its density and moisture-content technical report explains why density depends on moisture and specific gravity.
Common mistakes and safe use
Keep diameter measurements perpendicular to the log axis, use the same unit shown beside each field, and avoid substituting circumference for diameter. Confirm whether a published density is green, air-dry, or oven-dry. Bark and retained water can add weight, while cavities and decay can reduce it. For transport, compare the estimated total with legal payload limits and distribute the load appropriately. For lifting, use actual verified weight whenever possible and follow the equipment manufacturer's instructions; this calculator does not determine rigging configuration or safe working load.