Lumber weight, by size and by species
An 8-foot 2×4 in southern pine, dry-stamped and sitting at the 19% moisture content that stamp allows, weighs about 10.9 lb — 1.36 pounds per linear foot. The same stick in spruce-pine-fir is about 8.5 lb. Neither number means anything without the moisture content beside it, which is why every figure on this page carries one.
This page cites no building code. The 2021 IRC publishes what a piece of lumber may span, not what it weighs, and pretending otherwise would be a made-up citation. The weights here are worked from three published standards instead, each named next to the numbers it stands behind.
Why a lumber weight needs a moisture content
Wood carries water, and the water is heavy. A stick stamped S-DRY, KD19 or MC19 was at 19% moisture or below when it was surfaced — that is what the stamp means — and the same stick left inside a heated building will keep giving up water until it settles nearer 12%. Those two states are the two columns below, and the gap between them is real weight, not rounding.
Everything wetter than that is off this page on purpose. Green lumber and freshly treated lumber can sit above the fiber saturation point, where the weight depends on how much solution the piece took and how long it has been drying — numbers only whoever treated it can give you.
| Species group | Specific gravity (NDS) | Dry-stamped, at its limit — 19% moisture | Settled indoors — 12% moisture |
|---|---|---|---|
| Southern pine | 0.55 | 37.4 lb/ft³ | 36.3 lb/ft³ |
| Douglas fir-larch | 0.50 | 34.3 lb/ft³ | 33.2 lb/ft³ |
| Hem-fir | 0.43 | 29.8 lb/ft³ | 28.8 lb/ft³ |
| Spruce-pine-fir | 0.42 | 29.1 lb/ft³ | 28.1 lb/ft³ |
Specific gravity as assigned in NDS Supplement Tables 4A and 4B, on the basis those tables state — weight and volume when oven-dry. Densities at moisture content follow Wood Handbook Chapter 4. NDS source · handbook source
Weight per linear foot
Pounds per foot of stick, for lumber at the 19% moisture content a dry stamp allows — the heavy end of dry lumber. Multiply by the length you are carrying, or read the whole pieces in the next table.
| Size | Dressed | Southern pine | Douglas fir-larch | Hem-fir | Spruce-pine-fir |
|---|---|---|---|---|---|
| 2×4 | 1.5” × 3.5” | 1.36 | 1.25 | 1.09 | 1.06 |
| 2×6 | 1.5” × 5.5” | 2.14 | 1.96 | 1.71 | 1.67 |
| 2×8 | 1.5” × 7.25” | 2.83 | 2.59 | 2.25 | 2.20 |
| 2×10 | 1.5” × 9.25” | 3.60 | 3.30 | 2.87 | 2.81 |
| 2×12 | 1.5” × 11.25” | 4.38 | 4.02 | 3.49 | 3.42 |
Pounds per linear foot at 19% moisture content. Dressed sizes from NDS Supplement Table 1B. table source
What a whole piece weighs
The lengths a yard stocks, at the same 19% moisture content. Left to settle indoors to 12%, every figure below comes down about 3%.
| Size | 8 ft | 10 ft | 12 ft | 14 ft | 16 ft |
|---|---|---|---|---|---|
| Southern pine | |||||
| 2×4 | 10.9 lb | 13.6 lb | 16.4 lb | 19.1 lb | 21.8 lb |
| 2×6 | 17.1 lb | 21.4 lb | 25.7 lb | 30 lb | 34.3 lb |
| 2×8 | 22.6 lb | 28.3 lb | 33.9 lb | 39.6 lb | 45.2 lb |
| 2×10 | 28.8 lb | 36 lb | 43.3 lb | 50.5 lb | 57.7 lb |
| 2×12 | 35.1 lb | 43.8 lb | 52.6 lb | 61.4 lb | 70.1 lb |
| Douglas fir-larch | |||||
| 2×4 | 10 lb | 12.5 lb | 15 lb | 17.5 lb | 20 lb |
| 2×6 | 15.7 lb | 19.6 lb | 23.6 lb | 27.5 lb | 31.4 lb |
| 2×8 | 20.7 lb | 25.9 lb | 31.1 lb | 36.2 lb | 41.4 lb |
| 2×10 | 26.4 lb | 33 lb | 39.6 lb | 46.2 lb | 52.8 lb |
| 2×12 | 32.1 lb | 40.2 lb | 48.2 lb | 56.2 lb | 64.3 lb |
| Hem-fir | |||||
| 2×4 | 8.7 lb | 10.9 lb | 13 lb | 15.2 lb | 17.4 lb |
| 2×6 | 13.7 lb | 17.1 lb | 20.5 lb | 23.9 lb | 27.3 lb |
| 2×8 | 18 lb | 22.5 lb | 27 lb | 31.5 lb | 36 lb |
| 2×10 | 23 lb | 28.7 lb | 34.5 lb | 40.2 lb | 45.9 lb |
| 2×12 | 27.9 lb | 34.9 lb | 41.9 lb | 48.9 lb | 55.9 lb |
| Spruce-pine-fir | |||||
| 2×4 | 8.5 lb | 10.6 lb | 12.8 lb | 14.9 lb | 17 lb |
| 2×6 | 13.4 lb | 16.7 lb | 20 lb | 23.4 lb | 26.7 lb |
| 2×8 | 17.6 lb | 22 lb | 26.4 lb | 30.8 lb | 35.2 lb |
| 2×10 | 22.5 lb | 28.1 lb | 33.7 lb | 39.3 lb | 44.9 lb |
| 2×12 | 27.3 lb | 34.2 lb | 41 lb | 47.8 lb | 54.7 lb |
Pounds per piece at 19% moisture content, from the dressed section in NDS Supplement Table 1B and the specific gravity in NDS Supplement Tables 4A and 4B. An individual piece varies around these figures; wood is not a manufactured section.
Where these numbers come from
The stick's size. A nominal 2×4 does not measure 2 inches by 4. NDS Supplement Table 1B lists the dry dressed size of every one of these — a 2×4 at 1.5 by 3.5 inches, 5.25 square inches of section — and the same table publishes its own weight-per-foot block at six densities, so the arithmetic on this page can be checked against AWC's printed figures rather than taken on trust.
How heavy the wood is. NDS Supplement Tables 4A and 4B assign each species group a specific gravity, on the basis those tables state: weight and volume when oven-dry. That is the number in the first table above, and it is the only species-specific input anywhere on this page.
What the water does. Wood Handbook Chapter 4 publishes the relations between specific gravity, moisture content and density — Eq. (4-9), Eq. (4-11), Eq. (4-12), Eq. (4-13) and Eq. (4-14) in its own numbering. They are what turn an oven-dry specific gravity into a density at 19% or 12%, and they are checked here against the handbook's own worked example: white ash at 12% moisture, which it puts at 42.2 lb/ft³.
The last step is division. Area in square inches over 144, times the density in pounds per cubic foot, is pounds per foot of stick. That is all the arithmetic there is.
What these figures are not. They are the weight of the wood, for a species group at a stated moisture content — not for the individual piece in your hands, which varies around them, and not for a piece wetter than 19%. And a weight is not a load: where the lumber's own weight is the thing being checked — material stacked on a floor, or a member carrying it — that is a load question, and it belongs to an engineer rather than to this page.
Common questions
How much does a 2x4 weigh?
An 8-foot 2×4 in southern pine, dry-stamped and sitting at the 19% moisture content that stamp allows, weighs about 10.9 lb — 1.36 pounds per linear foot. The same 8-foot 2×4 in spruce-pine-fir, the lightest of the four species groups these span tables are read by, is about 8.5 lb. Both figures are for dry lumber; a treated 2×4 straight off the pile is a different and much heavier animal, and this page will not put a number on it.
Why does the same size of lumber weigh different amounts?
Two reasons, and both are on this page. The first is species: the four groups the 2021 IRC span tables are read by run from a specific gravity of 0.42 for spruce-pine-fir to 0.55 for southern pine, which is most of a third more wood in the same stick. The second is water. Wood weight moves with moisture content, so a weight quoted without one is not an answer — every figure here says which moisture content it assumes.
How much does pressure-treated lumber weigh?
More than the figures on this page, often a great deal more, and how much more is not something this site will guess at. Treated lumber leaves the cylinder carrying the treating solution, so a freshly treated board can be well above the fiber saturation point while a dry-stamped board of the same size is at 19% or below. The weight depends on the retention level, the treatment, and how long the piece has been drying since — ask your lumber yard, which knows what it sold you. What the code does say about treated lumber is which spans it is read at, and those are on the deck joist span pages.
How thick is a 2x4?
A nominal 2×4 is 1.5 inches thick: its actual size is 1.5 inches by 3.5 inches as dressed, which is an area of 5.25 square inches. Every size on this page is listed at its dry dressed dimensions in NDS Supplement Table 1B, and those dimensions — not the nominal name — are what the weights on this page are worked from.
Does the IRC say how much lumber weighs?
No, and this page does not cite it for one. The 2021 IRC publishes allowable spans, and the dead loads its span tables assume are loads on an assembly, not weights of a piece. The figures here come from three published sources named on this page: NDS Supplement Table 1B for the dressed section, NDS Supplement Tables 4A and 4B for the specific gravity assigned to each species group, and Wood Handbook Chapter 4 for the relation between specific gravity, moisture content and density.
The same four species, on the span tables
The species groups above are the ones the 2021 IRC span tables are read by, and each has a page carrying every table this site publishes for it: Southern pine · Douglas fir-larch · Hem-fir · Spruce-pine-fir
Sizing rather than carrying: floor joist spans · ceiling joist spans · rafter spans · deck joist spans — the deck page is also where the treated lumber question gets its real answer, since the deck table is the one with the wet service factor already in it.