Stud Calculator
With wall length 20 ft, stud spacing 16 inch, doors and windows 1, corners 2, stud comes to 24 studs — studs to order. It is reached in 5 steps, the last of which is 16 + 4 + 4, and each one is printed on the page with its numbers filled in. The formula is the one published by International Residential Code R602, not an approximation fitted to it.
Studs and plate lumber for a framed wall at 16 or 24 in on centre, including corners and openings.
Formula and sources checked · How we check
Wall length 20 ft, Stud spacing 16 inch, Doors and windows 1, Corners 2
24 studs
Studs to order for the example below. Editing a field recomputes the calculator below; this figure holds the answer the page was loaded with.
It is written into the HTML rather than drawn by a script, so a search engine reading this page without running JavaScript still finds an answer.
- Studs in the field
ceil(20 * 12 / 16) + 116 studs- Studs for openings
1 * 44 studs- Studs for corners
2 * 24 studs- Studs to order
16 + 4 + 424 studs- Plate lumber (one bottom, two top)
20 * 360 ft
Several at once
A job is rarely one of anything. Work out the first, add it, change the figures and add the next — the list keeps what each line was, and totals them.
Worked example
A 20 ft wall at 16 in on centre takes 16 field studs, plus 4 for one opening and 4 for two corners — 24 total, and 60 linear feet of plate for one bottom and two top plates. Order a few extra: crowned and twisted studs get culled on site.
How to work it out yourself
- 1.Measure the wall length in feet and multiply by 12 for inches.
- 2.Divide by the stud spacing and round up, then add one for the far end.
- 3.Add two studs per corner and four per opening — a king and a jack on each side.
- 4.Order three times the wall length in plate lumber: one bottom plate and a doubled top plate.
The formula
- Studs in the field
ceil(20 * 12 / 16) + 1 - Studs for openings
1 * 4 - Studs for corners
2 * 2 - Studs to order
16 + 4 + 4 - Plate lumber (one bottom, two top)
20 * 3
Source: International Residential Code R602 — wood wall framing, American Wood Council — wall framing spans and spacing
Questions people actually ask
- When can I frame at 24 inches?
- Non-bearing interior walls almost always, and bearing walls in many cases under advanced framing provisions — but the sheathing and drywall have to be rated for the wider span, and 1/2 in drywall visibly waves at 24 in on ceilings.
- Why does each opening add four studs?
- A king stud runs full height on each side, and a jack stud inside it carries the header — two per side. Wide openings also need a built-up header and cripples above, which are not counted here.
- Why three times the length in plates?
- One bottom plate and a doubled top plate. The double top plate ties intersecting walls together and lets you lap joints over a stud rather than in mid-air.
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