How the math works
Wall length in inches: 40 × 12 = 480"Spaces: 480 ÷ 16 = 30.00 → 30 full spacesLayout studs = spaces + 1 = 31+2 corner/end backers, +10% waste: (31 + 2) × 1.10 = 37Plates: 1 bottom + 2 top = 3 × 40' = 120 LF
Each door or window adds king, jack and cripple studs — roughly +3 studs per opening.
Trade pro tips
- Pull layout from the same end on walls, floors and roof so sheathing seams land on framing.
- Crown every stud the same direction.
- Add 1 stud per foot of wall as a quick sanity check on bigger takeoffs.
Frequently asked questions
How many studs do I need for a 40 ft wall?
At 16" on center: 31 on layout; buy 37 to cover corners/ends and 10% waste. Openings add about 3 studs each.
How many studs for a 40 ft wall at 24 inches on center?
21 on layout, 26 to buy with corners and waste.
How much plate lumber for a 40 ft wall?
120 linear feet for a bottom plate and double top plate — 8 sixteen-foot boards (stagger top-plate joints at least 24").
What length studs for an 8 ft wall?
92-5/8" precut studs: with a bottom plate and double top plate (4-1/2") the wall is 97-1/8", leaving room for 1/2" drywall on an 8' ceiling.