Formula Used
Frustum volume: V = πL(D₁² + D₁D₂ + D₂²) / 12
Smalian volume: V = L(A₁ + A₂) / 2
Huber volume: V = L × A midpoint
Small end volume: V = L × A small end
Net volume: gross volume × (1 − defect deduction)
Weight: net volume × density × moisture factor × bark factor × quantity
Dry basis moisture factor: 1 + moisture / 100
Wet basis moisture factor: 1 / (1 − moisture / 100)
How to Use This Calculator
Enter the log length and choose the correct unit.
Enter both end diameters. The tool will use the smaller and larger values.
Select a species preset, or enter your own density.
Choose whether density is oven dry or current field density.
Add moisture, bark allowance, defect deduction, and safety factor.
Select a volume method. Frustum is a balanced choice for tapered logs.
Press Calculate. The result appears above the form.
Use the CSV or PDF button to save the current calculation.
Example Data Table
| Species |
Length |
Small Diameter |
Large Diameter |
Density |
Moisture |
Estimated Weight |
| Douglas Fir |
12 ft |
16 in |
22 in |
530 kg/m³ |
45% |
About 815 kg |
| Oak |
10 ft |
14 in |
20 in |
700 kg/m³ |
50% |
About 906 kg |
| Pine |
8 ft |
12 in |
16 in |
420 kg/m³ |
35% |
About 252 kg |
Understanding Saw Log Weight
Saw log weight depends on volume and density. Volume comes from length and diameter. Density comes from species and moisture. A green oak log can weigh far more than a dry pine log. That difference matters during loading, hauling, milling, and storage. A useful estimate must consider taper, bark, defects, and count.
Why Shape Matters
Logs are not perfect cylinders. Most taper from butt end to small end. This calculator supports several volume models. The frustum method treats the log as a tapered solid. Smalian uses the average of both end areas. Huber uses the midpoint diameter. The small end method is conservative for many sawmill checks. Comparing methods helps you see the possible range.
Density and Moisture
Wood density is often listed as oven dry density. Field logs contain water. Moisture content raises actual weight. Dry basis moisture adds water as a percent of dry wood mass. Wet basis moisture treats water as a percent of total mass. This page lets you choose the basis. It also allows bark allowance and defect deduction. Those settings make the estimate closer to field conditions.
Practical Uses
A saw log weight estimate helps plan trailer loads. It also helps compare timber lots. Operators can avoid overloading chains, forks, winches, and vehicles. Sawmill owners can estimate inbound material weight before scaling. Firewood sellers can compare green and seasoned logs. Builders can estimate handling needs for beams or rounds.
Accuracy Tips
Measure diameter at right angles and average the readings. Use inside bark diameter when you want wood volume only. Add bark allowance when bark is being hauled. Measure log length along the centerline. Enter a realistic defect deduction for rot, hollow cores, sweep, checks, and heavy knots. Use a species density from a trusted table when possible.
Final Notes
The result is an engineering estimate. It should not replace certified weighing. It is best for planning and comparison. Actual weight can change with sapwood, heartwood, rain, mud, bark thickness, and storage time. For legal hauling, use a scale ticket or approved weight method.
Keep saved results with each timber load. Record species, moisture, method, and date. These notes improve future estimates and reduce loading surprises at the yard later.
FAQs
What is a saw log weight calculator?
It estimates the weight of a log from diameter, length, density, moisture, bark, defects, and quantity. It helps with loading, hauling, and milling plans.
Which volume method should I use?
Use frustum for a balanced tapered log estimate. Use Smalian for end-area averaging. Use Huber when a midpoint diameter is trusted. Use small end for conservative checks.
Does moisture content affect log weight?
Yes. Water can add major weight. Green logs are often much heavier than seasoned logs. Enter moisture carefully for a better field estimate.
What density should I enter?
Enter oven dry density when using moisture adjustment. Enter current field density when you already know the real wet density of the log.
Should bark be included?
Include bark when hauling whole logs. Set bark allowance to zero when measuring only wood volume or when bark has already been removed.
What is defect deduction?
It reduces usable volume for rot, hollow sections, cracks, sweep, and waste. A higher deduction lowers the estimated wood weight.
Is this result legal for hauling limits?
No. It is an estimate for planning. Use a certified scale or approved weighing method when legal load limits are involved.
Can I export my result?
Yes. Submit the form with the CSV or PDF button. The file will contain the main inputs and calculated weight results.