Board feet in a 5/4 x 8 x 12 board
At the rough size it is sold at
10 bd ft
1-1/4 × 8 in × 12 ft
By the NHLA tally
10 bd ft
From the standard, NHLA Rules (2019)
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.
- 5/4 is 1-1/4 in thick rough, and hardwood is billed at its rough size: 1.25 × 8 × 12 ÷ 12 = 10 bd ft.
- A hardwood yard tallies by the NHLA rule instead: the surface measure, 8 × 12 ÷ 12 = 8 sq ft, is rounded to a whole foot and multiplied by the thickness, which gives 10 bd ft.
- Surfaced two sides (S2S) it planes to 1-1/16 in, but it is still counted at the rough 1-1/4 in.
What a 5/4 x 8 x 12 weighs
The weight of the rough board, 0.833 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 |
|---|---|---|---|
| White oak | 0.68 | 47.5 | 39.6 lb |
| Red oak (northern) | 0.63 | 44.1 | 36.7 lb |
| Hard maple (sugar) | 0.63 | 44.1 | 36.7 lb |
| White ash | 0.6 | 42 | 35 lb |
| Black walnut | 0.55 | 38.5 | 32 lb |
| Black cherry | 0.5 | 35 | 29.1 lb |
| Poplar (yellow-poplar) | 0.42 | 29.4 | 24.5 lb |
One source: USDA Forest Products Laboratory, the authority for species properties it measured
5/4 x 8 in other lengths
| Board | Rough bd ft | NHLA tally |
|---|---|---|
| 5/4 x 8 x 8 | 6.67 | 6.25 |
| 5/4 x 8 x 10 | 8.33 | 8.75 |
| 5/4 x 8 x 12 | 10 | 10 |
How 5/4 is sized rough and surfaced is on the 5/4 lumber 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.