How many board feet in a 4x4x12?
By the name (nominal)
16 bd ft
4 × 4 in × 12 ft
By the actual dry size
12.25 bd ft
3-1/2 × 3-1/2 in × 12 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: 4 × 4 × 12 ÷ 12 = 16 bd ft.
- A dry 4x4 is dressed to at least 3-1/2 × 3-1/2 in under the softwood lumber standard, so the wood you get is 3.5 × 3.5 × 12 ÷ 12 = 12.25 bd ft.
- A yard that quotes softwood in board feet may count either size; ask which one it prices on.
What a 4x4x12 weighs
The weight of the dressed board, 1.021 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 | 34.3 lb |
| Southern pine (loblolly) | 0.51 | 35.7 | 36.4 lb |
| Western hemlock | 0.45 | 31.5 | 32.1 lb |
| Eastern white pine | 0.35 | 24.5 | 25 lb |
| White spruce | 0.36 | 25.2 | 25.7 lb |
One source: USDA Forest Products Laboratory, the authority for species properties it measured
A 4x4 in other lengths
| Board | Nominal bd ft | Actual bd ft |
|---|---|---|
| 4x4x8 | 10.67 | 8.17 |
| 4x4x10 | 13.33 | 10.21 |
| 4x4x12 | 16 | 12.25 |
| 4x4x14 | 18.67 | 14.29 |
| 4x4x16 | 21.33 | 16.33 |
The 4x4’s dry and green sizes, in inches and mm, are on the 4x4 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.