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Stud Framing Calculator

Wall length divided by stud spacing, plus one extra stud — the baseline count before openings and corners.

Wall length (ft)

Stud spacing, on-center (in)

Studs needed

16 inches on-center is the standard residential spacing; 24 inches is common for advanced framing.

What you entered

Wall length (ft): 20Stud spacing, on-center (in): 16

1
Wall length in inches
20 × 12= 240 in
2
Studs at 16" on-center, plus one extra
⌈240 ÷ 16⌉ + 1= 16 studs

Result

Studs needed: 16

A 20 ft wall at 16" on-center needs 16 studs — add extra for corners, openings, and blocking.

Studs needed for common wall lengths at 12, 16, and 24 inch on-center spacing

Each count is the baseline field stud count this calculator produces: wall length converted to inches, divided by the on-center spacing, rounded up, plus one stud to close the end of the run.

Wall length (ft)	Wall length (in)	Studs at 12 in OC	Studs at 16 in OC	Studs at 24 in OC
8	96	9	7	5
10	120	11	9	6
12	144	13	10	7
14	168	15	12	8
16	192	17	13	9
20	240	21	16	11
24	288	25	19	13
30	360	31	24	16
40	480	41	31	21
50	600	51	39	26

These are field studs for a plain wall run only. Real framing adds studs you must count separately: about 3 at each outside corner, 2 or more at every wall intersection, and roughly 4 per opening (2 king studs plus 2 jack studs) on top of the header. Plates are extra lumber, not studs. 16 in on-center is the residential standard and lines up with 4 x 8 sheet goods; 24 in on-center advanced framing saves lumber and leaves more room for insulation but needs to be checked against your local code for load-bearing walls.

16 vs. 24 inch spacing

16 inches on-center is the traditional residential standard, sized to match standard 4×8 sheet goods evenly. 24-inch spacing ('advanced framing') uses less lumber and improves insulation but requires careful engineering to still meet load requirements.

This is a baseline, not a full framing plan

Real framing needs additional studs at corners (typically 3), wall intersections, and around window and door openings (king studs, jack studs, headers) — this calculator gives the baseline field stud count for a plain wall run.

Frequently asked questions

My wall is 20 ft long — how many studs do I need at 16-inch on-center?

16 studs (20 ft = 240 inches / 16 = 15 spaces + 1 = 16 studs). That's the baseline for a plain wall run — add extras for corners and openings.

When should I use 24-inch spacing instead of 16-inch?

24-inch 'advanced framing' uses about 25% less lumber and provides better insulation. It works for single-story exterior walls and most interior walls, but requires engineering approval and may not satisfy code for load-bearing walls in multi-story construction.

How many extra studs do I need for a door opening?

A standard door opening adds 2 king studs (full height, flanking the opening) + 2 jack studs (supporting the header) + a header (typically doubled 2x lumber). That's 4 extra studs plus the header material, per opening.