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Stud Calculator

Calculator + chartEnter your measurements below and it works the answer out.

Studs in the field = wall length in inches ÷ spacing, plus one. Then add three per corner and four per opening. Enter the wall for the count and the plate length.

Describe the wall

Field studs by wall length

Wall length16 in centers24 in centers12 in centers
8 ft759
10 ft8611
12 ft10713
16 ft13917
20 ft161121
24 ft191325
30 ft231631
40 ft312141

Field studs only — the run of the wall, one at each end. Corners and openings are extra, and the calculator adds them.

How this was worked out

The count. Wall length in inches divided by the spacing gives the number of bays; add one to close the far end. A 20 ft wall is 240 inches, which is 15 bays at 16 in centers, so 16 studs in the field.

Why 16 inches. Sheet goods come in 4 ft widths, and 16 divides into 48 exactly three times, so every sheet edge lands on a stud. 24 in centers works for the same reason with two bays per sheet, and 12 in centers with four.

Corners take three. A standard framed corner uses three studs: two forming the corner itself and one turned to give the drywall on the inside face something to land on. Advanced framing gets it down to two with drywall clips, at the cost of a detail the drywaller has to know about.

Openings take four before anything else. Two king studs running full height and two jack studs carrying the header, one each side. The header itself, the cripples above it and the sill below a window are extra and depend on the span — this calculator counts the studs, not the structure.

Plates. Three times the wall length in linear feet: a single bottom plate and a doubled top plate. Buy in lengths that let you stagger the joints in the double top plate rather than stacking them.

What this does not count. Headers, cripples, blocking, bracing and fire stops all depend on the span and the load. Those come from a plan or an inspector, and no calculator should pretend otherwise.

Sources. The stud count is arithmetic — wall length divided by spacing plus one — and it is written out above. The three-stud corner and the two king plus two jack studs at an opening are standard US platform framing practice, not a published standard, and structural members such as headers are deliberately excluded because they are determined by span and load rather than by a rule of thumb. There is no published standard behind the three-stud corner or the four studs at an opening; both are standard US platform framing practice. Structural members are excluded because span and load decide them. Last reviewed 29 August 2026.

Common questions

How many studs do I need for a 20 foot wall?

16 in the field at 16 inch centers: 240 inches divided by 16 is 15 bays, plus one to close the end. Add three per corner and four per door or window on top of that.

How do I calculate studs for a wall?

Wall length in inches ÷ spacing, then add one. At 16 in centers a 12 ft wall is 144 ÷ 16 = 9, plus one, so 10 field studs.

Why are studs 16 inches apart?

Because sheet goods are 4 ft wide and 16 goes into 48 exactly three times, so every sheet edge lands on a stud. It is a spacing chosen to suit the sheets, not the timber.

Can I frame at 24 inch centers?

For many non-load-bearing and some load-bearing walls, yes, and it saves timber. It needs 5/8 in drywall on ceilings to avoid sag, and whether it is permitted for a bearing wall depends on the load and the code where you are.

How long are precut studs?

92 5/8 inches for an 8 ft wall and 104 5/8 for a 9 ft wall. The precut length plus a single bottom plate and a doubled top plate comes to the finished height, which is why the number looks odd on its own.

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