Framing by the numbers
Framing comes down to spacing: studs and joists are placed at 16 or 24 inches on-center, so the count is the length divided by the spacing plus one, with extras for corners, openings, and doubling. Sheet goods like plywood cover 32 sq ft each, and lumber is often sold and priced by the board foot. Because framing is structural, confirm member sizes and spans against your local code or an engineer.
Which calculator do I need?
- Wall framing calculator — studs, plates, and total 2×4s for a wall at 16 or 24 in on-center.
- Floor joist calculator — how many joists across a floor, plus rim joists.
- Plywood calculator — 4×8 sheets of plywood or OSB for a subfloor, wall, or roof.
- Board foot calculator — total board feet and cost of a hardwood lumber order.
- Stair calculator — steps, riser height, and total run from your floor-to-floor rise.
Framing is structural — size it right
These calculators count the material, but the member size is the part that matters most: a joist or stud has to be deep enough for its span and load. Use a span table (or an engineer) to pick the size, then count the pieces here. Remember the extras a bare count misses — headers over openings, king and jack studs, double top plates, blocking, and the subfloor or sheathing on top. A 10% waste allowance covers crooked boards and miscuts.