How many studs do I need?
For the field, divide the wall length in inches by the spacing and add one. A 24 ft wall at 16 in on centre is 288 ÷ 16 = 18, plus 1 = 19 studs. At 24 in on centre it is 13.
Then add everything the field count ignores. A three-stud corner takes 3, an intersecting wall needs a 3-stud channel to catch drywall, and every opening needs 2 king studs, 2 jacks, and cripples above — plus below, on a window. That 24 ft wall with two corners and two 3 ft openings goes from 19 to 37: 19 in the field, 6 for the corners, and 12 around the openings.
The rule of thumb people quote — one stud per linear foot — happens to land close for 16 in on centre walls with a normal number of openings, and it is close by coincidence rather than by arithmetic. It over-counts a blank wall and under-counts one full of windows.
How the calculation works
Field studs = ceiling(length in inches ÷ spacing) + 1. The +1 is the stud at the far end, and it is the one most often left off.
Stud length is the wall height minus the plates, not the wall height. A standard 8 ft wall with a bottom plate and a double top plate loses 4½ inches of plate, so the stud is 92⅝ in — which is exactly why precut studs are sold at that length. Change to a single top plate and it becomes 94⅛.
Openings need 2 kings (full height, either side), 2 jacks (carrying the header), and cripples filling between the header and the top plate at the same spacing as the field. A window adds cripples below the sill too.
Going from 16 to 24 in on centre removes roughly a third of the studs, which is the point of advanced framing — less lumber, less thermal bridging, more insulation. The trade-off is that drywall and sheathing edges span further, so 24 in walls usually want mid-height blocking and thicker drywall on the ceiling.
Typical framing lumber cost, mid-2026
| Material | Unit | Typical range |
|---|---|---|
| 2×4 precut stud (92⅝ in) | each | $3.20 – $6.50 |
| 2×6 precut stud | each | $5.50 – $11.00 |
| 2×4 × 16 ft plate stock | each | $12.00 – $26.00 |
| 2×4 pressure-treated bottom plateRequired on concrete | per lf | $1.20 – $2.80 |
| LVL header stock | per lf | $6.00 – $14.00 |
| Framing labour | per sq ft of wall | $4.00 – $10.00 |
The bottom plate on a slab must be pressure-treated or separated from the concrete. Untreated lumber in contact with concrete wicks moisture and is a termite invitation.
What goes wrong on this job
- Order 10% extra and expect to use it. Crowned, twisted and split studs get culled at the pile, not at the wall, and a stud that will not straighten is not a stud.
- Buy precut studs rather than cutting 8-footers. They are cheaper per piece, they are all identical, and cutting 30 of them by hand introduces exactly the variation that makes a wall out of plane.
- Mark the plates together. Lay the bottom and top plate side by side, hook the tape once, and mark both — that guarantees every stud is plumb before you have nailed anything.
- Lay out from one end, not from each corner inwards. Sheathing and drywall come in 4 ft widths and land on the layout only if the layout starts at zero and never resets.
- Set the first stud at 15¼ in, not 16. That puts the centre of the stud at 16 in so the sheet edge lands on half of it, which is the whole point of the spacing.
Frequently asked questions
How many studs do I need for a 24 foot wall?
19 field studs at 16 in on centre, or 13 at 24 in. Add 3 per corner, 3 per intersecting wall, and 6 per 3 ft opening — a 24 ft wall with two corners and two openings needs 37.
How long is a precut stud?
92⅝ inches for an 8 ft wall. That is 96 in less a 1½ in bottom plate and a 3 in double top plate.
Is 16 or 24 inch stud spacing better?
16 in is the default and required for some sheathing and siding. 24 in — advanced framing — uses about a third less lumber and cuts thermal bridging, but needs blocking for drywall edges and checks against span tables.
How many studs per linear foot?
Roughly one, for a 16 in on centre wall with a normal number of openings. It is a coincidence of the arithmetic rather than a rule, and it fails badly on walls that are mostly glass.
What size header do I need?
Prescriptive tables cover up to about 6 ft for a single-storey load with a double 2×10 or an LVL. Beyond that, or with a floor above, get the span sized rather than guessing.