Wood Log Weight Calculator
Navigate the intricacies of log weight calculations with precision using our Wood Log Weight Calculator. Tailored for those in the forestry sector, timber trade, and woodworking crafts, this tool alleviates the guesswork from estimating the weight of round timber. Enter the log's dimensions, select the species, and let the calculator provide an immediate estimate of weight, aiding in transport planning, cost estimation, and project management. For those working with timber in various shapes and sizes, we also offer a comprehensive wood weight tool to suit all your needs.
In short: Log weight = volume x density. The volume of a round log is pi x radius2 x length, so a 3 m log with a 300 mm average diameter holds about 0.21 m3. Multiply by the species density (kg per m3) and allow for moisture - freshly felled logs are the heaviest. Enter your logs below for an estimate in kg.
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Understanding the weight of raw timber immediately after harvesting is a critical step for anyone involved in the logging industry or those utilising firewood for energy. Our Wood Log Weight Calculator is engineered to provide you with accurate weight estimates for logs in their natural, round form. This tool is indispensable for calculating transportation loads, estimating potential timber yield, and managing stock levels for firewood sales.
For those in forestry and agriculture, precisely gauging the weight of freshly cut logs ensures that vehicles are loaded safely and within legal limits. It also helps in predicting the amount of usable material that will be available once the wood has been processed. In the context of firewood, weight calculations assist in determining the value of wood before it enters the market, ensuring fair pricing and proper inventory management.
How much do logs weigh? Green vs seasoned weights by species
On our model a log at 80% moisture weighs about 33% more than the same log kiln dried to 10%, because much of a green log's weight is water. The table shows the weight of one cubic metre of solid wood for common UK log species at four moisture levels, using the same densities and moisture factors as the calculator above.
| Species | Kiln Dried - 10% (kg/m3) | Air dried - 20% (kg/m3) | Fresh sawn - 40% (kg/m3) | 80% (kg/m3) | One 3 m log, 300 mm diameter, fresh sawn |
|---|---|---|---|---|---|
| Oak (European) | 756 | 792 | 864 | 1,008 | 183 kg |
| Ash (European) | 746 | 781 | 852 | 994 | 181 kg |
| Beech (European) | 756 | 792 | 864 | 1,008 | 183 kg |
| Birch (European) | 693 | 726 | 792 | 924 | 168 kg |
| Sweet chestnut | 620 | 649 | 708 | 826 | 150 kg |
| Larch (European) | 620 | 649 | 708 | 826 | 150 kg |
| Douglas fir | 557 | 583 | 636 | 742 | 135 kg |
| Norway spruce | 425 | 446 | 486 | 567 | 103 kg |
| Sitka spruce | 452 | 473 | 516 | 602 | 109 kg |
A 3 m log with a 300 mm average diameter holds about 0.21 m3 of wood (pi x 0.15 m x 0.15 m x 3 m). Multiply by the figure for your species and moisture, or enter your own logs in the calculator.
How accurate are these figures?
We checked our densities against the published figures on The Wood Database. For very wet wood we also used a second method: above about 30% moisture a log no longer shrinks or swells, so its density is its basic specific gravity x (1 + moisture content) x 1,000 kg/m3 (USDA Wood Handbook, 2021, chapter 4). At 80% moisture that is basic specific gravity x 1,800.
| Species | Our base density (kg/m3) | Wood Database dried weight, about 12% moisture (kg/m3) | Our model at 80% | Cross-check at 80% | Difference |
|---|---|---|---|---|---|
| Oak (European) | 720 | 675 | 1,008 | 954 | +6% |
| Ash (European) | 710 | 680 | 994 | 882 | +13% |
| Beech (European) | 720 | 710 | 1,008 | 954 | +6% |
| Birch (European) | 660 | 640 | 924 | 900 | +3% |
| Sweet chestnut | 590 | 590 | 826 | 900 | -8% |
| Larch (European) | 590 | 575 | 826 | 810 | +2% |
| Douglas fir | 530 | 510 | 742 | 810 | -8% |
| Norway spruce | 405 | 405 | 567 | 576 | -2% |
| Sitka spruce | 430 | 425 | 602 | 648 | -7% |
At 80% moisture our model and the cross-check differ by between -8% and +13% across these species, so treat any log weight as an estimate. Real logs vary: moisture differs between heartwood and sapwood, between species, and with the season the tree was felled.
Why green logs are heavier
Moisture content is the weight of water in the wood as a percentage of the weight of the dry wood. A log at 80% moisture carries 0.8 kg of water for every 1 kg of wood. As it seasons the water evaporates, so the log gets lighter while the amount of wood stays the same. That is why the calculator asks for moisture as well as species and size.
Need timber cut from logs? WoodUBuy sells sawn timber cut to size, and WoodUChoose makes bespoke mouldings and profiles. Species properties are on AnyOneWood.
The moisture content of wood, which significantly influences its weight, is a variable that cannot be overlooked. A log's weight can fluctuate based on its water content, affecting everything from the drying process to its burning efficiency as firewood. For a deeper understanding of this factor, read our comprehensive guide on how moisture content impacts timber weight.
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