🧱 Wall Stud Calculator
Enter the wall length and stud spacing to get the number of studs, with extra studs for doors and windows and the plate material.
16
studs (incl. openings)
40 ft
plate material (top + bottom)
Studs = ⌈wall length ÷ spacing⌉ + 1 (the +1 is the end stud), plus roughly two extra studs per door or window opening (king and jack). Plate material is the wall length doubled for the top and bottom plates. Standard spacing is 16″ on-center (24″ for some non-load-bearing walls). Add studs for corners and partition intersections. 🔒 In your browser.
How the wall stud calculator works
The number of studs is the wall length divided by the on-center spacing, rounded up, plus one for the end of the wall: studs = ⌈length ÷ spacing⌉ + 1. Each door or window opening adds roughly two more studs (a king and a jack stud on each side, simplified here). Plate material is the wall length doubled — one top plate and one bottom plate.
This is a framing estimate for a straight wall at 16-inch on-center spacing (the standard for load-bearing walls; 24-inch is used for some non-load-bearing walls). Add extra studs for corners, T-intersections with partition walls, and the cripple studs above and below openings. Buy a few spare — real framing always uses more than the minimum.
Frequently asked questions
How many studs do I need for a wall?
Divide the wall length by the stud spacing and round up, then add one for the end: for a 20-ft wall at 16 in on-center, that's ⌈240 ÷ 16⌉ + 1 = 16 studs, before extras for openings and corners.
What is 16 inch on center?
"On center" (OC) means the spacing measured from the centre of one stud to the centre of the next. 16-inch OC — a stud every 16 inches — is the standard for load-bearing walls; it also lines up with 4×8 sheet goods.
How do doors and windows change the stud count?
Each opening needs king studs (full height, on each side) and jack studs (supporting the header), so it adds studs even though the opening removes some. This tool adds about two studs per opening as a simple allowance.
How much plate material do I need?
Two lengths of the wall — a bottom plate and a top plate (often a double top plate, which would be three). The tool shows the wall length doubled; add a plate length if your design uses a double top plate.
Should I use 16 or 24 inch spacing?
16-inch OC is standard for load-bearing walls and gives a stiffer wall; 24-inch OC ("advanced framing") uses less lumber and is allowed for many non-load-bearing and some engineered walls. Follow your plans and local code.