Calculate the number of studs, plates, and lumber needed to frame a wall, plus total material cost, from wall length, height, and stud spacing.
Framing Formula
The number of studs in a wall is found from the wall length and the on-center spacing:
Studs = (L * 12 / OC) + 1 + (Corners * Ec) + (Openings * Eo)
The linear feet of plate material depends on how many plate rows the wall uses:
Plate LF = L * Rows
The material cost adds the studs and the plate boards together:
Cost = (Studs * Ps) + (Plate boards * Pb)
- Studs is the total number of vertical studs the wall needs.
- L is the wall length in feet (multiplied by 12 to convert to inches).
- OC is the on-center spacing between studs in inches, usually 16 or 24.
- Corners is the count of corners and T-intersections, and Ec is the extra studs added at each one.
- Openings is the number of doors and windows, and Eo is the extra studs added per opening for king and jack studs.
- Plate LF is the total linear feet of plate lumber, where Rows is the number of plate rows (2 for a single top plate, 3 for a double top plate).
- Ps is the price per stud and Pb is the price per plate board.
The calculator works in three modes. The full wall mode counts studs, plates, and total lumber from the wall length, height, spacing, openings, and plate style. The quick stud count mode returns just the stud total for one or more identical walls. The cost estimate mode applies your stud and plate prices, plus a waste allowance, to turn the material counts into a budget. The "+1" in the stud formula accounts for the stud at the far end of the wall, and the waste allowance pads the totals so you order enough to cover offcuts.
Common Spacing and Plate Reference
The table below shows roughly how many studs a wall needs at the three common spacings before adding extras for corners and openings.
| Wall length | 12 in OC | 16 in OC | 24 in OC |
|---|---|---|---|
| 8 ft | 9 | 7 | 5 |
| 10 ft | 11 | 9 | 6 |
| 12 ft | 13 | 10 | 7 |
| 16 ft | 17 | 13 | 9 |
| 20 ft | 21 | 16 | 11 |
Plate rows depend on the wall type. The reference below shows how many rows of plate lumber to count for the linear-foot total.
| Wall type | Bottom plates | Top plates | Total rows |
|---|---|---|---|
| Non load bearing (single top) | 1 | 1 | 2 |
| Load bearing (double top) | 1 | 2 | 3 |
Example Problems
Example 1. You are framing a 16 ft wall at 16 in on center with one door opening and two corners, adding 2 extra studs per corner and 2 per opening.
Base studs are (16 * 12 / 16) + 1 = 12 + 1 = 13. Corners add 2 * 2 = 4 and the opening adds 1 * 2 = 2, for a total of 19 studs.
Example 2. The same 16 ft wall is load bearing, so it uses a double top plate, which is 3 plate rows. The plate lumber is 16 * 3 = 48 linear feet. With 8 ft plate boards, that is 48 / 8 = 6 boards.
FAQ
What stud spacing should I use?
Most interior and load-bearing walls are framed at 16 in on center. Some non-load-bearing and exterior sheathed walls can go to 24 in on center, which uses fewer studs. Use 12 in on center where extra strength or heavy finishes call for it. Check your local building code, since the required spacing can depend on the wall load and stud size.
Why does the calculator add extra studs for corners and openings?
A plain run of wall needs one stud per spacing interval plus one at the end. Corners and T-intersections need additional studs to tie walls together and to back the drywall, and every door or window needs king studs, jack studs, and cripples. Adding a few studs per corner and per opening keeps the count realistic instead of leaving you short.
How much waste allowance should I include?
A waste allowance of 5 to 10 percent is common for framing lumber. It covers offcuts, damaged boards, and miscut pieces. Order on the higher end if your wall has many openings or angles, since those produce more short, unusable pieces.
