TradesHow this works
Enter the wall length, height, and corner count, and say whether the wall is load-bearing. The tool works out studs, plate lumber, and sheathing sheets, and lays the two common stud spacings side by side. Sixteen inches on center is the stiffer, standard choice for structure. Twenty-four inches saves lumber and leaves room for insulation on walls that do not carry load.
This is the base wall run plus a corner allowance. Openings need their own king, jack, and cripple studs and a header, so add those on top. And where the plans or code call a spacing, that decision wins over any lumber saving.
Common questions
How many studs do I need for a wall?
Divide the wall length in inches by the on-center spacing, round up, and add one to end the run. A 20 foot wall at 16 inches on center is about 16 studs before corners. Add two studs per corner, and more for every door and window opening.
Should I frame at 16 or 24 inches on center?
Sixteen inches on center is stiffer and the standard for load-bearing and exterior walls, with better backing for drywall and siding. Twenty-four inches, called advanced framing, uses about 30 percent fewer studs and leaves more room for insulation, and it suits non-load-bearing and energy-first walls. Your plans and local code have the final say.
Why do 16 and 24 inches both work?
Sheet goods like drywall and sheathing are 48 inches wide. Both 16 and 24 divide evenly into 48, so every sheet seam lands on a stud. That is why these two spacings are the standard and why odd spacings cause trouble at the seams.
What plates do I need?
A standard wall has one bottom plate and a double top plate, so the plate lumber is three times the wall length. The double top plate ties walls together and carries load across the studs, so it is not optional on a structural wall.
Does this count door and window openings?
No. This is the base wall run plus a corner allowance. Every opening needs its own king and jack studs, cripples above and below, and a header sized for the span. Those are added on top, and a wall full of openings frames heavier than the on-center count alone.
Sources: Studs = ceil(length_in / OC) + 1; 12 ft wall = 10 studs at 16 in, 7 at 24 in (Inch Calculator, Omni) · 24 in OC uses ~30% fewer studs and more insulation; 16 in OC is stiffer for load-bearing (BuildCalculate) · Standard wall: single bottom plate + double top plate; sheathing 4x8 = 32 sq ft sheets. Engine version 1.0.0. Risk tier 2.