How it's calculated
Studs = ⌈L × 12 ÷ spacing⌉ + 1 + corners + 5 × doors + 7 × windows, × 1.10
L = wall length (ft), spacing = 16 or 24 in on-centre, corners = 2 or 3 studs each, plus framing per door and window. × 1.10 adds 10% waste.
Common questions
What stud spacing should I use?
16 inches on center is the most common for load-bearing walls. 24 inches is allowed for some non-load-bearing walls.
Why are there two plates?
A wall has a bottom plate and a top plate that the studs nail into, so plate length is twice the wall length.