Stud calculator
Studs = wall length in inches ÷ 16, rounded up, plus one, then one each side of an opening and one per corner: a 14 ft wall with a window and two corners takes 16 studs, or 18 with 10% extra.
Example: replace these measurements
Your framing list
18 2x4 studs+ 1 more item on the list
18 2x4 studs
Your shopping list
- 18 2x4 studs
- 3 plate boards, 16 ft
Quantities and package details
- Bedroom wall
- 12 on 16-in centers + 2 at openings + 2 at corners = 16 studs
- Studs before extra
- 16
- Studs to buy
- 18
- Stud length
- 92 5/8 in, the precut stud for an 8 ft wall
- Plate lumber
- 42 ft (bottom plate and double top plate)
- Plate boards, 16 ft
- 3
The calculation
- Bedroom wall: 168 in ÷ 16 = 10.5, rounded up, + 1 = 12 studs; + 2 × 1 opening + 2 corners = 16
- 16 × (1 + 10/100) = 17.6, rounded up to 18 studs
- Plates: 3 × 14 ft = 42 ft; whole 16-ft boards for each full board length in a row, and the shorter pieces cut from shared boards: 3 boards
Not measured yet? Common sizes
A rough starting point, worked out with this calculator. Walls 8 ft high, no openings or corners; the number to buy adds 10% extra. Plate boards are 16 ft boards for the bottom plate and the double top plate; pieces shorter than a board are cut from shared boards, so a 20 ft wall takes four. Walls framed 24 in apart take fewer studs, where your plans and local code allow it. Use a row to load its size into the calculator, then change it to your measurements.
| Wall | Studs 16 in apart | Studs 24 in apart | Plate boards | Load |
|---|---|---|---|---|
| 8 ft wall | 7, buy 8 | 5, buy 6 | 3 | |
| 10 ft wall | 9, buy 10 | 6, buy 7 | 3 | |
| 12 ft wall | 10, buy 11 | 7, buy 8 | 3 | |
| 14 ft wall | 12, buy 14 | 8, buy 9 | 3 | |
| 16 ft wall | 13, buy 15 | 9, buy 10 | 3 | |
| 20 ft wall | 16, buy 18 | 11, buy 13 | 4 |
Common questions
How many studs do I need for a wall?
For studs on 16-inch centers, divide the wall length in inches by 16, round up and add one. A 12 ft wall is 144 ÷ 16 = 9, plus one: 10 studs. Add one on each side of a door or window and one at each corner, then about 10% for crooked boards.
How long are studs for an 8 ft wall?
92 5/8 inches. Sold as precut studs, they make a wall of 97 1/8 inches with a bottom plate and a double top plate, so 8 ft drywall reaches the ceiling with room for the ceiling board.
16 or 24 inches on center?
16 inches is the usual spacing for walls; 24 inches uses fewer studs and is common with 2x6 exterior walls. Your plans and the local code decide which a wall may use.
How many plates does a wall need?
Three rows the full length of the wall: one bottom plate and a double top plate. A 14 ft wall takes 42 ft of plate lumber, or three 16 ft boards. The IRC lets plate joints fall between studs, as long as the end joints in the two top plates are at least 24 inches apart and the top plates overlap at corners and where bearing walls meet. So a 20 ft wall takes four 16 ft boards: three full lengths, and the three 4 ft ends cut from the fourth. Your inspector has the final word.
Source: International Residential Code 2021, R602.3.2 Top plate. Listed on the Sources page.
How to plan the quantity
Studs on 16-inch centers: wall length in inches ÷ 16, rounded up, plus one for the end. A 14 ft wall is 168 ÷ 16 = 10.5, so 11 spaces and 12 studs.
Add one stud on each side of every door or window for the king and jack studs, and one at each corner or where another wall meets this one. Then add about 10% for crooked or split boards.
Plates run the full length three times: one bottom plate and a double top plate. For an 8 ft wall, buy precut studs of 92 5/8 inches: with the three plates the wall comes to 97 1/8 inches: room for the ceiling drywall, with full 8 ft sheets on the walls below it. For 9 and 10 ft walls the precuts are 104 5/8 and 116 5/8 inches.
Before you order
- Stud size, spacing and the header over each opening come from your plans and the local code: this counts boards, it does not size them.
- Headers, cripple studs, blocking and fire blocking add lumber this does not count. Ask the lumber yard to check the list against the plan.
Before ordering, read the guide: How many sheets of drywall do I need? Sheets, tape, mud and screws. Or choose another calculator.