Stud Calculator

Enter your wall length and pick an on-center spacing — that is all most people need. The default 16 in OC is the standard for load-bearing walls in the US. Open More options to switch to metric, add corner studs, allow for waste, or add a price per stud for a quick cost. The result is the total number of vertical studs, plus the lineal feet of top and bottom plate lumber.

"On center" (OC) means the distance from the center of one stud to the center of the next. To find how many wall studs you need, divide the wall length by the OC spacing to get the number of bays, then add one stud for the far end of the wall. That is why a perfectly even wall still needs an "extra" stud: a 20 ft wall at 16 in OC has 15 bays but 16 studs, one on each bay line. Real walls also need extra studs at corners, at T-intersections where a partition meets, and on each side of every door and window opening. Use Studs at each wall end and Extra studs to add those without redoing the math.

Bays = ⌈ wall length (in) ÷ OC spacing (in) ⌉

Studs = Bays + 1 + extra corner and opening studs

The calculator converts your wall length to inches, rounds the bays up to a whole number (you can't buy a partial bay), then adds one end stud. Corner selections add studs at each end, and any waste allowance is applied last and rounded up to whole studs.

Example 1 — a 24 ft garage wall at 16 in OC: 24 ft = 288 in. 288 ÷ 16 = 18 bays, + 1 = 19 studs.

Example 2 — a 12 ft bedroom wall at 24 in OC: 12 ft = 144 in. 144 ÷ 24 = 6 bays, + 1 = 7 studs.

Example 3 — a 16 ft wall at 16 in OC with two corners (2 studs per end): 16 ft = 192 in. 192 ÷ 16 = 12 bays, + 1 = 13, plus one extra stud at each end = 15 studs.

- 16 in OC is code-minimum for most load-bearing walls — confirm your local code before stepping out to 24 in OC.
- Add 2 studs per opening (king + jack) plus a header for every door and window; put those in the *Extra studs* box.
- Plates run the full length of the wall: one bottom plate and a double top plate means about 3× the wall length in lineal feet of plate lumber.
- Buy a 10% waste allowance for offcuts, crooked studs, and mistakes — the *Waste allowance* option does this for you.
- Studs are sold by length (92⅝ in "precut" for 8 ft walls). This tool counts *how many*, not the wall height.