Board feet in a 1×8×12
There are two honest answers. The wood you actually carry out of the store is 5.44 board feet — a 1×8 really measures 0.75″ × 7.25″. But if you're pricing or trading lumber, the industry counts this board as 8.00 BF, because board feet are by convention figured on the nominal 1″ × 8″ name.
The math, both ways
trade (nominal): 1″ × 8″ × 144″ ÷ 144 = 8.00 BF
Which one do you want? If you're figuring weight, volume, or "how much wood is that really," use 5.44. If you're comparing against hardwood priced per board foot, or reading a mill tally, use 8.00 — the whole trade runs on nominal, for the historical reasons on our nominal vs actual page. (Construction lumber itself is usually priced per piece, so at the store neither number appears on the shelf tag.)
What a 1×8 is for
The 1×8 is the classic board-and-batten siding field board, the barn-siding size, and a favorite bookshelf depth for paperbacks. At 7-1/4″ actual, two of them edge-glued make a 14-1/2″ panel — the traditional route to cabin shelving and bench seats.
Wider boards mean wider seasonal movement: a pine 1×8 can change width by an eighth of an inch between summer and winter. Board-and-batten exists precisely to let each board move behind a batten that hides the shifting gap.
Twelve feet divides evenly into 16″ and 24″ on-center layouts, which makes it the blocking-and-plate length framers reach for. It still fits in most garages and on most roof racks — the last length that's easy to haul without flags and straps.
Heft check: at its true 0.75″ × 7.25″ section, a 12′ board holds 0.45 ft³ of wood — about 16 lb kiln-dried, and closer to 25 lb dripping fresh off the pressure-treated rack.
What that volume costs at hardwood prices
| Price per BF | Actual wood (5.44 BF) | Trade tally (8.00 BF) |
|---|---|---|
| $3.00 | $16.31 | $24.00 |
| $5.00 | $27.19 | $40.00 |
| $7.00 | $38.06 | $56.00 |
| $10.00 | $54.38 | $80.00 |