Quick answer: Stud count = wall length (in inches) ÷ on-center spacing (16 or 24 in) + 1, plus extra studs for each corner and opening. Plates run the wall length × 2–3.
Enter your wall length and stud spacing to find the number of studs and the linear feet of top and bottom plate material.
For a standard stick-framed wall, the number of vertical studs is driven by the wall length and the on-center (O.C.) spacing. The basic formula is:
Field studs = (wall length in inches ÷ spacing) + 1
The "+1" accounts for the stud at the end of the wall. On 16-inch centers — the most common spacing — a 20-foot wall needs (240 ÷ 16) + 1 = 16 field studs before extras. This calculator then adds studs for each corner and each opening, because corners need extra studs to back drywall and openings need king and jack studs.
Every wall needs a bottom (sole) plate and a top plate. Most load-bearing walls use a double top plate, so the total plate material is about three times the wall length. This calculator returns that linear footage so you can buy the right number of long boards.
On 16-inch centers, a 20-foot wall needs about 16 field studs, plus extras for corners and openings — typically 20 to 24 studs total once you include corners and a door or window.
16 inches on center is the standard for load-bearing exterior and interior walls. 24-inch spacing is used in advanced framing and some non-bearing walls.
Start with the field-stud count, then add king and jack studs for each opening (roughly two extra per opening) and extra studs at corners. This tool adds those allowances automatically.
Multiply the wall length by three for a double top plate plus single bottom plate. A 20-foot wall needs about 60 linear feet of plate material.
Last reviewed August 2026 · how we source these figures
Field studs only, at 16 in and 24 in on-centre, before corner and opening extras. Plate figure is three plates: one bottom, two top.
| Wall length | Studs @ 16" o.c. | Studs @ 24" o.c. | Plate lumber |
|---|---|---|---|
| 8 ft | 7 | 5 | 24 ft |
| 10 ft | 9 | 6 | 30 ft |
| 12 ft | 10 | 7 | 36 ft |
| 16 ft | 13 | 9 | 48 ft |
| 20 ft | 16 | 11 | 60 ft |
| 24 ft | 19 | 13 | 72 ft |
| 30 ft | 24 | 16 | 90 ft |
| 40 ft | 31 | 21 | 120 ft |
Add two studs per corner and two per opening (king and jack), then about 10% for waste. A 20 ft wall at 16 in o.c. works out to 16 field studs plus extras.
Every constant this calculator uses and where it comes from, so you can check it rather than take our word for it.
Local codes amend the model IRC and adopt different cycles — your building department governs. Manufacturers revise yields; where your product's data sheet disagrees with a default here, use the product's number. See our full methodology.