Lumber Weight Calculator
Work out what a stack of lumber weighs at any moisture content, by species, and whether the vehicle you are collecting it in can legally carry it.
How to use this calculator
- 1Pick the moisture content honestly. Green and kiln dried differ by half again, and it is the commonest source of a badly wrong answer.
- 2Enter dimensions in the rough if the wood is rough - a nominal 1 in board that is really 1-1/8 in is 12% heavier than the nominal figure.
- 3If you are collecting the wood, set the vehicle. Payload runs out well before space does with dense hardwood.
- 4Use the comparison table to see how much of the weight is water, which is what will disappear over the drying period.
How the calculation works
Ovendry density = published density at 12% / 1.12
Volume ratio(m) = tangential factor(m) x radial factor(m), both referenced to 12%
Density(m) = ovendry density x (1 + m / 100) / volume ratio(m)
Weight = volume x density(m); board feet = thickness x width x length / 144- m
- Moisture content as a percentage of the ovendry weight
- Published density
- Wood Handbook density at 12% moisture content, in lb per cubic foot
- Volume ratio
- How much the wood has swollen or shrunk relative to its size at 12%, from the shrinkage coefficients
- Board foot
- 144 cubic inches of wood - a unit of volume, not of weight or of area
Moisture changes weight twice over. It adds the water directly, and it swells the wood so that the same mass occupies more space. Ignoring the second effect over-estimates green density by several percent.
Run backwards to green, the model gives 65 lb per cubic foot for red oak against the 64 commonly published, and 44 at 12% by construction. That agreement at the far end of the range is the check that the volume term is being handled correctly.
Above the fibre saturation point the volume stops changing, so density from there upwards rises purely with the added water. That is why the green figures for different species converge more than their dry figures do.
Worked example
A pickup load of kiln-dried oak
- 1.Twenty boards at 1 x 8 x 96 in is 8.89 cubic feet, or 107 board feet.
- 2.Red oak is 44 lb per cubic foot at 12% moisture; at 8% it has less water and has shrunk slightly, working out near 43.2.
- 3.So the load is about 384 lb - a quarter of a half-ton pickup’s payload, and entirely comfortable.
- 4.Space runs out long before weight does with dried hardwood in modest quantities, which is why people underestimate what a full load weighs.
Result: About 384 lb - well within a half-ton payload
The same volume, green off the mill
- 1.Same twenty boards, but freshly sawn at 80% moisture content.
- 2.The wood has swollen back to its green dimensions and is carrying water equal to 80% of its ovendry weight, giving about 65 lb per cubic foot.
- 3.The load is now around 580 lb - just over half again the dried figure.
- 4.Scale that up to a real mill run and the difference decides whether a trailer is legal.
Result: About 582 lb - 52% heavier than the same boards dried
When payload runs out: 500 board feet of hickory
- 1.500 board feet is 41.7 cubic feet, which fits in a pickup bed without much trouble.
- 2.Hickory at 12% is 51 lb per cubic foot - the densest common North American hardwood.
- 3.That is 2,125 lb, well past a half-ton truck’s 1,500 lb payload, so it needs two trips.
- 4.At 4.25 lb per board foot, this vehicle carries about 353 board feet of hickory a load - against roughly 620 of yellow poplar.
Result: 2,125 lb - two trips in a half-ton, or one in a three-quarter
Where the weight comes from
Wood is a cellular solid, and the substance the cell walls are made of has almost the same density in every species - around 1.5 times the density of water. What differs between species is how much of a given volume is cell wall and how much is empty cavity. Balsa is mostly cavity; lignum vitae is mostly wall, which is why it sinks.
That single fact explains most of the useful behaviour. Denser woods are stiffer, harder, stronger and heavier in the same proportion, because all four properties track the amount of actual cell wall material present. It is why a species chart that ranks woods by density also ranks them, roughly, by everything else a woodworker cares about structurally.
Moisture then sits on top. Water in the cell cavities adds weight without adding anything else, and water in the cell walls adds weight and swells the wood as well. Green lumber can be a third water by weight, and the whole of that third eventually leaves.
Board feet, and why they are not weight
A board foot is a unit of volume: 144 cubic inches, which is a piece 1 inch thick, 12 inches wide and 12 inches long, or anything equivalent. It exists because lumber is sold by how much wood you get, and it works well for that.
It works badly as a proxy for anything else. A board foot of eastern white pine weighs a little over two pounds; a board foot of hickory weighs more than four. Anyone who has loaded a truck by counting boards rather than by weighing them has discovered this, usually at the point the rear suspension bottoms out.
The other trap is nominal against actual dimensions. Construction lumber is sold at nominal sizes that are smaller once surfaced - a 2 by 4 is 1.5 by 3.5 inches - so a nominal board foot of dimensional stock contains only about two thirds of the wood the name implies. Hardwood sold rough is the opposite: a 4/4 board is a full inch or slightly more, and it is measured before surfacing.
- Green — 60% to 100% moisture content for hardwood, and softwood sapwood can exceed 150%. Freshly sawn.
- Air dried — 12% to 16% depending on climate. The floor that outdoor drying can reach.
- S-DRY — Construction lumber surfaced at 19% moisture or less. Not furniture dry.
- Kiln dried — 6% to 8% for furniture stock. The only condition that matches a heated house.
Payload, and the number on the door jamb
Vehicle payload is the maximum weight of everything you add to the vehicle: cargo, passengers, tools, fuel beyond what was in it when it was weighed, and any accessories fitted afterwards. It is printed on a sticker in the driver’s door opening, and on a modern half-ton pickup it is frequently a good deal less than the "half ton" name suggests - well-equipped crew cabs can be down around 1,300 pounds.
Dense hardwood reaches that figure faster than the bed fills. Five hundred board feet of hickory is about a fifth of the volume of a pickup bed and comfortably over the payload of a light truck, and green lumber is worse again.
The failure mode is not usually dramatic. An overloaded light truck stops taking corners well, takes noticeably longer to brake, and works its tyres and rear suspension harder than they were designed for - all of which are survivable until something else goes wrong at the same time. It is also, in most jurisdictions, an offence, and it invalidates the insurance position in a way that only becomes relevant after a collision.
What this assumes, and where it stops
Assumptions
- Density is derived from the Wood Handbook figure at 12% moisture content, adjusted for both the water carried and the volume change at other moisture contents.
- Dimensions entered are actual rather than nominal. Construction lumber sold as 2 by 4 is really 1.5 by 3.5 inches.
- Volume change is taken as the product of the tangential and radial changes, longitudinal movement being negligible.
- Vehicle payload figures are typical for the class and are no substitute for the sticker in your own door opening.
Limitations
- Species averages vary widely in reality. Density within a single species commonly spans 20% and occasionally much more, so a stack can be noticeably heavier or lighter than calculated.
- It assumes solid wood. Plywood, MDF and particleboard have their own densities - MDF in particular is heavier than most solid softwoods.
- Logs are not lumber. A log includes bark and an irregular shape, and log volume rules deduct for both, so this page will not price or weigh a log correctly.
- Payload is only one of the limits on a vehicle. Gross combined weight, axle ratings and tyre load ratings all apply, and the lowest of them governs.
- Green moisture content varies enormously between heartwood and sapwood in the same board, particularly in softwoods, where sapwood can be twice the heartwood figure.
Common questions
How much does a board foot of oak weigh?
About 3.7 lb kiln dried at 8% moisture, and about 5.4 lb green. Red and white oak are close enough for most purposes at 44 and 47 lb per cubic foot respectively at 12%. Divide by twelve to get the per board foot figure, since a board foot is a twelfth of a cubic foot.
Why is green lumber so much heavier?
Because moisture content is measured against the ovendry weight, so wood at 80% moisture content is carrying water equal to 80% of the wood itself - it is about 44% water by total weight. All of that leaves during drying. It is also why a green log feels so different from the boards that eventually come out of it.
Can my pickup carry a thousand board feet?
It depends entirely on the species and the moisture. A thousand board feet of dry yellow poplar is about 2,400 lb; the same in green white oak is over 5,000. A half-ton pickup handles neither. Check the payload sticker in the door opening rather than the truck’s marketing name, and remember that passengers and tools come out of the same allowance.
Does a board foot mean the same thing for hardwood and construction lumber?
The unit does, but what you get differs. Hardwood is measured rough, before surfacing, so a 4/4 board really is about an inch thick. Dimensional construction lumber is named at a nominal size and sold surfaced below it, so a nominal board foot of 2 by 4 contains roughly two thirds of the wood the name implies. Use actual measured dimensions here.
How do I weigh wood without a scale?
You do not need to - volume times density is reliable to within the natural variation between boards, which is the limiting factor either way. If you want a check on a specific board, weigh one piece on a bathroom scale and scale up; that captures whatever is unusual about that particular stack better than any published average can.
Sources
- Wood Handbook: Wood as an Engineering Material (FPL-GTR-282), chapter 4, physical properties — USDA Forest Service, Forest Products Laboratory
Formula and content last reviewed on .
Results are estimates for information only, not professional advice.
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