Stairs, decks, rafters, and lumber — cut lists and layouts you can take to the saw.
Lumber does not come in the length you need — it comes in the length the yard stocks, and a cut list that ignores that is a shopping list with waste built in. These calculators think in boards and cuts. A stair stringer is solved to a legal, even riser rather than a decimal; rafters resolve to a length and a plumb cut; deck framing returns joists, boards, and the fastener count that actually goes with them. Board feet and linear feet are kept distinct, because the yard prices one and you buy the other. Nominal versus actual dimensions are handled where it matters, which is everywhere a thickness stacks up.