Well, that seems right, doesn't it?!
But I think there may be a catch...and I think it's the source of my problem. Some of the lumber websites indicate that board feet is based on the original plank before it's milled....not on the eventual 3/4 in. thick plank.
That seems crazy to me, since one has no way of knowing that. But that's what they said.
Not so crazy...
If it's the rough plank, then the most likely "original" thickness is 1" (before planing), so that makes the problem even easier.
Your number of board-feet is your original area, 240 b-f.
Of course, this is a guess. The mill is the only source of the accurate plank dimension before planing and after planing.
So they need to provide that.
Alternatively, you can give them the "finished" area in square feet and let them figure out what the rough board-feet area is.
you're correct about before vs after
2 by 4s aren't really 2 inches by 4 inches either ,, just like a country mile isn't really a country mile,, :)