How many studs for a 20 ft wall?
A 20 ft (6.10 m) wall needs 16 studs at 16″ on center or 11 at 24″, plus extra studs for corners and openings. The calculator below is set to a plain 20 ft, 8 ft high wall — add doors and windows to see the full list.
Wall
Height is to the top of the top plate. 8′ 1 1/8″ uses 92 5/8″ precut studs with a double top plate. Lengths accept 12, 12' 6" or 150".
Doors, windows & T-walls
| Type | From start in | Width in | Height in | Sill in | Header | Remove |
|---|
Rough-opening sizes. "From start" is the distance from the start of the wall to the left edge of the rough opening (for a T-wall, to the face of the partition). Header sizes are your choice for estimating lumber — size load-bearing headers from your local code's header table or an engineer.
- Common stud
- King stud
- Jack stud
- Header
- Cripple
- Rough sill
- Corner / T backing
- Blocking
- Plates
Lumber to buy
| Item | Size | Length | Net | Buy |
|---|---|---|---|---|
| Studs | 2×4 | 92 5/8″ | 16 | 18 |
| Plates | 2×4 | 20′ | 3 | 3 |
Stud length 92 5/8″ (cut from 92 5/8″ precut studs). Short pieces are packed into stud-length boards with a 1/8″ kerf. About 199 ft of lumber in total.
Cut list
| Part | Size | Length | Qty |
|---|---|---|---|
| Bottom plate | 2×4 | 240″ | 1 |
| Top plates (double) | 2×4 | 240″ | 2 |
| Studs (full length) | 2×4 | 92 5/8″ | 16 |
Layout marks
Hook the tape on the start of the wall and mark the near edge of each stud at: 15 1/4, 31 1/4, 47 1/4, 63 1/4, 79 1/4, 95 1/4, 111 1/4, 127 1/4, 143 1/4, 159 1/4, 175 1/4, 191 1/4, 207 1/4, 223 1/4 in (centres at 16″ multiples).
Planning estimate only. Header sizes, stud grades, load paths and fire blocking depend on loads, species, grade and your local building code. Verify with your building department or a licensed professional before you buy or build.
Stud count for a 20 ft wall
| Spacing | Plain wall | + 3-stud corners both ends | Buy (+10%) |
|---|---|---|---|
| 12″ o.c. | 21 | 25 | 28 |
| 16″ o.c. | 16 | 20 | 22 |
| 19.2″ o.c. | 14 | 18 | 20 |
| 24″ o.c. | 11 | 15 | 17 |
The count is 240 ÷ spacing, rounded up, plus one for the stud at the start. 92 5/8″ precut studs make a 97 1/8″ (8 ft) wall with a double top plate.
With a door
Put a 36″ door (38″ × 82 1/2″ rough opening, 2×12 header) in the middle and the wall at 16″ takes 16 full-length studs, 2 jack studs and 2 cripples. Layout marks inside the opening become cripples, and marks that land on the king or jack studs are dropped.
Plates
Bottom plate plus double top plate: three runs of 20 ft = 3 boards (20′ each run). Joints in the double top plate should be offset at least 24″.
Layout marks at 16″ on center
15 1/4, 31 1/4, 47 1/4, 63 1/4, 79 1/4, 95 1/4, 111 1/4, 127 1/4, 143 1/4, 159 1/4, 175 1/4, 191 1/4, 207 1/4, 223 1/4 in (near edge of each stud), with end studs at 0 and 238 1/2 in.
Other lengths: 8 ft, 10 ft, 12 ft, 14 ft, 16 ft, 24 ft, 30 ft, 32 ft, 40 ft · all lengths 4–40 ft. Background: stud spacing explained.
FAQ
How many studs for a 20 ft wall at 16 inches on center?
16 studs: 240 ÷ 16 = 15, rounded up to 15, plus 1. With three-stud corners at both ends it is 20; buy 18 with 10% waste for the plain wall.
How many studs for a 20 ft wall at 24 inches on center?
11 studs (240 ÷ 24 rounded up, plus 1).
How many plates for a 20 ft wall?
A bottom plate and a double top plate are three runs of 20 ft: 3 boards (20′ per run). Offset the top plate joints at least 24″.
How many studs for a 20 ft wall with a door?
A 36″ door (38″ × 82 1/2″ rough opening) in the middle of a 20 ft wall at 16″ on center needs 16 full-length studs (including 2 kings), 2 jack studs and 2 short cripples above a 2×12 header.