Framing Stud Calculator
Estimate the studs for a wall from its length, the on-center spacing, openings and corners.
How it works
studs = floor(length × 12 ÷ spacing) + 1, plus 2 per opening, plus 3 for corners/backing
On-center studs come from the wall length in inches divided by the spacing, plus one to close the end. Each door or window adds a pair of studs (king plus jack) to frame it, and corners and partition intersections need extra studs for backing and drywall nailing — three is a common allowance for a single wall. Add 10% for crowned or split lumber you set aside.
Worked example
A 20 ft wall at 16 in on center: 240 ÷ 16 = 15, plus 1 is 16 on-center studs. Two openings add 4 and corners add 3, for 23 studs — about 25 with waste — plus 60 ft of plate lumber.
Frequently asked questions
16 or 24 inch on center?
Sixteen inches is the residential default and required for many load-bearing and shear conditions; 24 in “advanced framing” saves lumber and works for non-bearing walls and some engineered assemblies. Load path and code decide, not preference.
What extra studs do openings and corners need?
Each opening needs a king stud plus a jack (trimmer) that carries the header, and wider openings add more jacks. Corners and wall intersections need backing studs so drywall has something to fasten to — easy to forget until sheeting day.
How much lumber for plates?
Standard walls have three plates — one bottom and a doubled top — so plate lumber is about three times the wall length. This calculator totals that separately from the studs.
Related calculators
Estimates only — add for waste and confirm against local building codes and supplier specs.