How many board feet in a 2x4x8?
By the name (nominal)
5.33 bd ft
2 × 4 in × 8 ft
By the actual dry size
3.5 bd ft
1-1/2 × 3-1/2 in × 8 ft
From the standard, NIST PS 20-25
The math
- A board foot is 144 cubic inches: a piece 1 in thick, 12 in wide and 1 ft long. So board feet = thickness (in) × width (in) × length (ft) ÷ 12.
- By the name: 2 × 4 × 8 ÷ 12 = 5.33 bd ft.
- A dry 2x4 is dressed to at least 1-1/2 × 3-1/2 in under the softwood lumber standard, so the wood you get is 1.5 × 3.5 × 8 ÷ 12 = 3.5 bd ft.
- A yard that quotes softwood in board feet may count either size; ask which one it prices on.
What a 2x4x8 weighs
The weight of the dressed board, 0.292 cubic feet, at 12% moisture content: volume × the Wood Handbook’s density, 62.43 lb/ft³ × its specific gravity at 12% × 1.12. Wood wetter than 12% weighs more; the wood weight calculator works it out at any moisture content.
| Species | Specific gravity (12%) | lb/ft³ | Weight |
|---|---|---|---|
| Douglas-fir (coast) | 0.48 | 33.6 | 9.8 lb |
| Southern pine (loblolly) | 0.51 | 35.7 | 10.4 lb |
| Western hemlock | 0.45 | 31.5 | 9.2 lb |
| Eastern white pine | 0.35 | 24.5 | 7.1 lb |
| White spruce | 0.36 | 25.2 | 7.3 lb |
One source: USDA Forest Products Laboratory, the authority for species properties it measured
A 2x4 in other lengths
The 2x4’s dry and green sizes, in inches and mm, are on the 2x4 actual size page. Every board side by side is on the board feet chart, and a whole order, with cost and waste, goes in the board foot calculator.
Work it out for your project
- Estimate the lumber for a whole project
List the parts, get the boards and board feet to buy, with waste.