Example Data Table
| Species |
Length |
Large Dia. |
Small Dia. |
Moisture |
Approx. Weight |
| Red Oak |
12 ft |
24 in |
20 in |
45% |
About 1,680 lb |
| Douglas Fir |
16 ft |
22 in |
18 in |
35% |
About 1,520 lb |
| Eastern White Pine |
10 ft |
18 in |
16 in |
40% |
About 520 lb |
Formula Used
Frustum volume: V = π × L × (D1² + D1 × D2 + D2²) ÷ 12
Hollow volume: H = π × h² × L ÷ 4
Adjusted volume: AV = (V − H) × (1 − defect %) × (1 + bark %)
Adjusted density: AD = base density × (1 + moisture %)
Weight: W = AV × AD × quantity
Safe planned weight: SW = W × (1 + safety factor %)
How to Use This Calculator
Choose the wood species first. Select custom density when your species is not listed. Enter the log length and both end diameters. Use the same value for both diameters when the log is nearly straight. Add hollow core diameter only when the log has a center void. Enter moisture, bark, defect, quantity, and safety values. Press the submit button. Review the result above the form. Use CSV or PDF export to save the calculation.
Why log weight matters
Log weight affects safe hauling, crane choice, milling cost, and yard storage. A log can look manageable and still be heavy. Diameter changes weight fast because area grows with the square of diameter. Length also matters, yet species and moisture often decide the final load. Dense hardwoods weigh more than light softwoods. Fresh timber can carry a large water mass.
Main inputs
This calculator uses length, end diameters, species density, moisture content, bark allowance, defect loss, and quantity. You may enter equal diameters for a straight cylinder. You may enter large and small end diameters for a tapered stem. The tool then uses a frustum volume. That model is better for real logs than a simple cylinder. A hollow core can also be removed from the volume.
Practical planning
The result gives weight for one log and for the full batch. It also shows volume, board foot estimate, load margin, and suggested trip count. The safety factor lets you add a planning buffer. This is useful when mud, bark, ice, or scale error may affect handling. A truck limit field helps compare the batch against a known payload rating.
Better estimates
Use measured diameters inside bark when you want wood mass only. Use outside bark when handling total log weight. Select a species close to the real timber. If the species is not listed, choose custom density. For green logs, moisture may range widely. Saw logs, firewood logs, and veneer stems can all vary. Treat results as estimates, not certified scale tickets.
Export and record
After calculation, export the result as CSV or PDF. Keep these files with job notes, delivery records, or sawmill estimates. The example table shows typical inputs. You can replace them with field measurements. Good records make future hauling safer and faster. Check each measurement twice before dispatch. Round diameters only after recording them. A small rounding error can become large on oversized timber. Review local road rules, bridge ratings, and machine limits before loading. When logs are irregular, measure several points and use the average. For valuable timber, compare this result with a certified scale or professional forester report. This gives records and fewer surprises during transport and unloading on site.
FAQs
What does this calculator estimate?
It estimates log weight from length, diameter, species density, moisture, bark, defects, and quantity. It also gives volume, board feet, payload margin, and trip count.
Why are two diameters used?
Real logs are often tapered. Two diameters let the calculator use a frustum shape, which is usually better than a simple cylinder estimate.
Can I use one diameter only?
Yes. Enter the same value for large and small end diameter. The formula will behave like a cylinder for a straight log.
What density should I choose?
Pick the closest species from the list. Use custom density when you have a local value from a mill, forestry guide, or scale record.
How does moisture affect weight?
Moisture increases calculated density. A green log can weigh much more than an air-dry log of the same size and species.
What is bark allowance?
Bark allowance adds a percentage to handling weight. Use it when your diameters are taken inside bark or when bark is thick and wet.
What does defect loss mean?
Defect loss reduces usable volume. It can represent rot, cracks, missing sections, checks, insect damage, or other visible volume loss.
Is this result legal for hauling?
No. It is only an estimate. Always follow local road limits, equipment ratings, axle rules, and certified scale requirements before hauling.