The weight is volume times density, and one of those is honest
The volume is exact. A 2x4 is 1-1/2 by 3-1/2 inches, so eight feet of it is 504 cubic inches, which is 0.2917 cubic feet. That number is not in dispute and it comes straight out of the dressed dimensions, which is why every calculation on this page uses actual sizes rather than the nominal name. A 2x10 is 9-1/4 inches wide, not 10, and using the name would overstate its weight by 8 percent.
The density is the soft half. Wood weight is dominated by how much water is in it, and the range is enormous. Kiln-dried SPF at around 30 pounds per cubic foot gives an 8 foot 2x4 at just under 9 pounds, which matches what people find when they weigh one. The same stick green, before drying, can be over 40. Pressure-treated lumber straight from the yard is often still saturated with treatment solution and lands nearer 50, which is why a treated 6x6 you can barely shift in June is manageable in October after a summer in the sun.
Working figures
| Material | lb per cu ft | 8 ft 2x4 | 8 ft 2x10 |
|---|---|---|---|
| Western red cedar, dry | 23 | 6.7 lb | 17.7 lb |
| Hem-fir, kiln dried | 28 | 8.2 lb | 21.6 lb |
| SPF, kiln dried | 30 | 8.8 lb | 23.1 lb |
| Douglas fir-larch, kiln dried | 33 | 9.6 lb | 25.4 lb |
| Southern yellow pine, kiln dried | 36 | 10.5 lb | 27.8 lb |
| Green softwood | 40 | 11.7 lb | 30.8 lb |
| Treated, still wet | 50 | 14.6 lb | 38.5 lb |
Treat every one of those as a working figure with real spread around it, not a specification. Species groups like SPF and hem-fir are commercial groupings that contain several actual species with different densities, graded and sold together. Moisture content moves the answer more than the choice of row. If you need the weight to be right rather than approximately right, put one piece on a bathroom scale and multiply.
Payload is the number that catches people
Payload is on a sticker in the driver door jamb and it is smaller than most people assume, frequently well under 1,500 pounds on a half-ton pickup once the trim and options are counted. It also includes everything in the vehicle: the driver, passengers, fuel, the toolbox and whatever has been living in the bed since spring. Two adults and a load of tools is 400 pounds before a single board goes on.
Sixty treated 2x6 at 12 feet, still wet, is around 1,400 pounds. That is a delivery, not a trip. And the failure mode is not usually dramatic — it is a truck that stops badly, steers vaguely and eats tyres. Where the load is close to the limit, the honest options are two trips or a delivery charge, and the delivery charge is nearly always the cheaper of the two once your time is in the sum. For the pulling side of the problem there is a towing and payload calculator.
Where lumber weight matters besides the truck
Dead load in a structure is largely the framing weighing itself. When you put a dead load figure into the header and beam load calculator, this is the arithmetic underneath it: joists, sheathing, finish and framing summed over an area and divided by that area. A floor framed in 2x10 SPF at 16 inch centers is roughly 1.4 pounds per square foot of joist alone, which is a small part of a 10 to 15 psf floor dead load but not a negligible one.
It also matters for handling. There is a practical difference between a piece one person carries and a piece that needs two, and it sits somewhere around 70 to 80 pounds for an awkward long object. A 16 foot treated 2x12 that is still wet is over 90 pounds and 16 feet long, which is a two-person lift regardless of how strong one of them is. Working that out before the delivery arrives is better than working it out in the driveway.
For volume and pricing rather than weight, the board foot calculator converts the same dimensions into the unit lumber is actually sold in, and the firewood cord calculator handles stacked round wood, which is a different problem entirely because of the air in the pile.
Questions people ask
How much does an 8 foot 2x4 weigh?
A kiln-dried SPF stud, the common one, is a little under 9 pounds. The arithmetic: 1.5 by 3.5 by 96 inches is 504 cubic inches, or 0.2917 cubic feet, times about 30 pounds per cubic foot. Douglas fir is closer to 10 pounds and southern yellow pine to 10.5. The same 2x4 in treated lumber straight from the yard, still wet, can be 14 or 15 pounds. If you have handled both you already know the difference; the number just puts a figure on it.
Why is pressure treated lumber so much heavier?
Because it is full of water. Treatment forces a waterborne preservative solution deep into the wood under pressure, and unless the yard bought material that was kiln dried after treatment, it comes out saturated and goes straight onto the rack. That water is a large fraction of the weight and it leaves over the following months as the wood dries in place. This is also why treated lumber shrinks, twists and pulls fasteners after installation more than kiln-dried stock does, and why decking laid tight when wet opens up into a gap later.
How accurate are the densities on this page?
They are working figures rather than specifications, and moisture content is a bigger source of variation than the species row you pick. Commercial groupings like SPF and hem-fir contain several species with genuinely different densities, sold together under one grade stamp. A piece that has sat in a dry heated space for a year weighs meaningfully less than the same piece off the rack. Expect the answer to be within roughly 10 to 15 percent for dry material and considerably looser for anything wet. Where the number has to be right, weigh a sample and scale it.
How much lumber can I put in a pickup?
Look at the payload sticker in the door jamb rather than at the bed. Payload is often lower than people expect and it counts everything: driver, passengers, fuel, tools and whatever is already in the bed. Enter it in the field here and the calculator shows the load as a percentage of it. Length is a separate constraint from weight — a 16 foot board in a 6 foot bed is mostly outside the truck regardless of what it weighs, needs flagging and tying, and shifts the balance rearward. Two trips or a delivery is often the correct answer and it is not an admission of anything.
Does this work for plywood and OSB?
Not directly, because sheet goods are a different material with their own densities, and a sheet is described by thickness rather than by a nominal section. As orientation, a 4 by 8 sheet of 3/4 inch plywood is commonly around 60 to 70 pounds and the same size in OSB is heavier again, with real variation by product. If you need a figure, use the custom option with the sheet thickness and 48 inches as the width, one foot at a time, or weigh a sheet. The sheet count itself comes off the plywood sheet calculator.