Wall Studs Calculator – How Many Studs Do I Need? | CalcLoft
Enter your wall length and stud spacing to find out exactly how many studs you need — with a 10% waste allowance built into your buy list.
How many studs do I need for a wall?
For a straight wall run, count studs from the formula studs = wall length in inches ÷ spacing, rounded up, + 1 for the stud at the far end:
Studs needed = roundUp(wall length in ft × 12 ÷ spacing) + 1
For example, a 10 ft wall framed at 16 in on center is 120 in long: 120 ÷ 16 = 7.5, rounded up to 8 spaces, plus 1 end stud = 9 studs. With the default 10% extra for cuts and waste, buy 10 studs.
Studs needed for common wall lengths
| Wall length | Studs @ 16 in OC | Buy (+10%) | Studs @ 24 in OC | Buy (+10%) |
|---|---|---|---|---|
| 8 ft | 7 | 8 | 5 | 6 |
| 10 ft | 9 | 10 | 6 | 7 |
| 12 ft | 10 | 11 | 7 | 8 |
| 16 ft | 13 | 15 | 9 | 10 |
| 20 ft | 16 | 18 | 11 | 13 |
These figures use studs = roundUp(length in in ÷ spacing) + 1 and buy = roundUp(studs × 1.1), the same basis as the stud spacing guide. They cover full-height studs in a plain wall only — openings and load-bearing walls add framing (see below).
Openings, corners and load-bearing walls
Every door or window opening needs extra vertical framing around it: king studs on the outside, jack (trimmer) studs under the header, plus the header itself. As a budget rule, plan on roughly 4 extra studs per opening on top of the plain-wall count. Corners and intersecting walls add a few more for nailing surfaces, and load-bearing walls need a properly sized header over every opening — confirm spans and loads with your local building code before you buy lumber.
Related guides
Wall studs calculator FAQ
How many studs do I need for a 10 ft wall?
At 16 in on center a 10 ft wall (120 in) needs 9 studs: 120 ÷ 16 = 7.5, rounded up to 8 spaces, plus 1 end stud. With the standard 10% extra you would buy 10. At 24 in on center the same wall needs 6 studs and you would buy 7.
16 in or 24 in on center — which should I use?
16 in on center is the most common for walls: drywall edges land on a stud with no blocking, and the wall feels stiffer. 24 in on center uses about a third fewer studs (6 vs 9 on a 10 ft wall), which suits many non-load-bearing interior partitions — but check your local code before framing anything structural with it.
How many extra studs do doors and windows add?
Plan on roughly 4 extra studs per opening for the king studs, jack studs and header support. For example, a plain 10 ft wall with one door jumps from about 9 studs to around 13. Load-bearing walls also need a sized header over each opening, so treat that count as a starting estimate.
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