Wall Stud Calculator
Calculate wall studs and top/bottom plate lumber from wall length, stud spacing, and wall count. Includes a 15% allowance for corners and openings.
How this calculator works
Studs are spaced evenly along a wall, plus extras for corners and openings; plates run the full length of the wall several times over. The calculator spaces the studs, adds a framing allowance, and multiplies wall length by your plate count.
Formula: Studs per wall = ⌊(wall length in ÷ spacing)⌋ + 1. Total studs = studs per wall × walls × 1.15 (rounded up). Plate linear feet = wall length × plates × walls.
Worked example
A 20 ft wall, 16-inch spacing, one wall, three plate rows:
- Studs per wall: ⌊(240 ÷ 16)⌋ + 1 = 16 studs
- Total with 15% for corners/openings: ⌈16 × 1.15⌉ = 19 studs
- Plate lumber: 20 × 3 = 60 linear feet
Spacing reference
| Wall length | Studs at 16 in OC | Studs at 24 in OC |
|---|---|---|
| 10 ft | 9 | 6 |
| 20 ft | 16 | 11 |
| 30 ft | 24 | 16 |
How to measure
Measure each wall’s length along the plate line. Count doors and windows — heavy opening counts push you toward the upper end of the waste allowance. Feed your total wall length into the Drywall Calculator next to sheet the finished framing.
Frequently asked questions
What stud spacing should I use?
16 inches on center is standard for load-bearing walls and works with standard 4-foot sheet goods. 24 inches on center is allowed for many non-load-bearing and single-story walls and uses less lumber. Set the spacing to match your plan.
Why add 15 percent to the stud count?
The base count spaces studs evenly along the wall, but real walls need extra studs at corners, wall intersections, and around every door and window opening (king studs, jack studs, and cripples). The 15 percent allowance covers typical framing; a wall with many openings may need more.
How much plate lumber do I need?
Plates are the horizontal members at the top and bottom of the wall. A standard wall has three plate rows — one bottom plate and a doubled top plate — so plate lumber equals the wall length times three. The calculator multiplies by your plate count.
Does this count studs for multiple walls?
Yes. Enter the number of walls of the same length, or run the calculator once per wall length and add the results for a room with different wall sizes.
What length studs do I buy?
Pre-cut studs sized for 8-foot walls (about 92⅝ inches) are standard and cheaper than cutting down longer stock. For taller walls, buy the next standard length and cut to your rough-opening height.
Estimates only. Verify quantities with your supplier before purchasing.