How much does a 2x4 weigh?

A kiln-dried 8-foot 2x4 in Douglas fir weighs about 10 lb. Green stock is heavier and pressure-treated heavier again. Weights for every common length and nominal size.

An 8' kiln-dried Douglas fir 2x4 weighs about 9.9 lb.

That is 1.24 lb per foot. A hundred of them is 992 lb, which is most of a half-ton pickup's payload before you get in it.

How that is worked out

  1. The dressed section is 1 1/2" × 3 1/2", so 8 feet of it is 0.29 ft³.
  2. Kiln-dried Douglas fir runs about 34 lb/ft³ at the moisture content lumber is sold at.
  3. 0.29 ft³ × 34 lb/ft³ = 9.9 lb.

Weight of one piece, kiln-dried, lb

Weight of one piece, kiln-dried, lb
Length2x42x62x82x102x12
8'9.915.620.526.231.9
10'12.419.525.732.839.8
12'14.923.430.839.347.8
14'17.427.335.945.955.8
16'19.831.241.152.463.8

Worth knowing

  • Green lumber carries water the kiln took out: at 37% moisture the same 8' stick works out at 11.5 lb, about 16% heavier.
  • Pressure-treated stock is heavier again, and for two reasons at once: it leaves the plant saturated with waterborne preservative, and it is usually southern yellow pine, which is denser than fir to start with. It sheds much of that water over a few weeks in the open.
  • Species matters more than anything else here. Southern yellow pine is roughly a third heavier than the same stick in white pine.
  • A density is a good bet across a stack and no promise about one board. Wood varies between trees, and the piece you pick up may be a pound either side.