Stud Calculator
Calculate how many studs and plates you need to frame a wall at 16 or 24 in on center, including extra studs for corners and openings and 10% waste.
By CalcBuilt Editorial TeamUpdated September 9, 2026Formulas checked against manufacturer specs, see how we calculate.
Results
- Studs to buy
- 29 studs
- 16 field studs + 6 for corners + 4 for openings, plus 10% waste
- Plate lumber
- 60 ft
- Bottom plate plus double top plate (3 x wall length)
- 16 ft plate pieces
- 4 pieces
- 2x4 or 2x6 to match the studs; use treated lumber for a bottom plate on concrete
- Stud length
- 92.625 in
- With three 1.5 in plates the wall stands 97.125 in tall
- Headers
- 1 header
- Size each header to its span: doubled 2x6 up to about 4 ft, 2x10 or 2x12 for wider openings, per local code
Stud formula
Field studs = Wall length (in) / spacing, rounded up, + 1
Extra studs = Corners x 3 + Openings x 4
Studs to buy = (Field + Extra) x (1 + waste %)
Plate lumber (ft) = 3 x Wall length (bottom plate + double top plate)Worked example
A 32 ft garage wall framed 24 in on center with 2 corners and 3 openings: 32 x 12 / 24 = 16, plus 1 = 17 field studs. Add 6 for corners and 12 for openings = 35. With 10% waste, 38.5, so buy 39 studs. Plates: 3 x 32 = 96 linear ft, or six 16 ft 2x4s.
Quick reference
| Wall length | 16 in on center | 24 in on center |
|---|---|---|
| 8 ft | 7 | 5 |
| 10 ft | 9 | 6 |
| 12 ft | 10 | 7 |
| 16 ft | 13 | 9 |
| 20 ft | 16 | 11 |
| 24 ft | 19 | 13 |
| 32 ft | 25 | 17 |
How to calculate studs for a wall
Convert the wall length to inches and divide by the on-center spacing. Round up and add one for the end stud. That gives the field studs. Then add the framing that does not follow the layout: three studs at each corner or intersection so there is backing for drywall, and at least four at each opening for the king and jack studs, plus short cripples above and below.
Order 10 percent extra. Some studs in every bundle are bowed or split, and straight ones are needed at corners, openings and anywhere cabinets will hang.
Plates, headers and spacing
Every wall gets a bottom plate and a double top plate, so plate lumber is three times the wall length. Buy 16 ft pieces and stagger the top plate joints away from the bottom plate joints.
16 in on center is standard for load-bearing walls and lines up with 4 ft sheet goods. 24 in on center saves lumber and is allowed for many non-bearing walls and advanced framing, but check the span tables in your local code before using it on a bearing wall.
Key facts
- At 16 in on center, a wall needs about one stud per 16 in of length plus one; at 24 in, one per 2 ft plus one.
- Precut studs are 92-5/8 in long so that with three 1-1/2 in plates the wall comes to 97-1/8 in, which fits 8 ft drywall with room for the ceiling.
- Each corner uses 3 studs and each door or window opening uses at least 4 (two king studs and two jack studs).
- A 20 ft wall at 16 in on center uses about 29 studs once corners, one opening and waste are counted.
- Bottom plates on a concrete slab must be pressure-treated or separated by a moisture barrier.
Frequently asked questions
How many studs do I need for a 20 foot wall?
16 field studs at 16 in on center, plus 3 per corner and 4 per opening. With two corners, one door and 10% waste that is 29 studs.
How many studs are in a 16 ft wall?
13 at 16 in on center or 9 at 24 in on center, before corners, openings and waste.
Why are precut studs 92-5/8 inches?
So that with a bottom plate and a double top plate (three 1-1/2 in plates) the wall stands 97-1/8 in, which leaves room for 8 ft drywall on the walls plus a 1/2 in ceiling and a gap at the floor.
Should I frame at 16 or 24 inches on center?
16 in is the default for bearing walls and gives stiffer walls and easier drywall. 24 in uses about 30% fewer studs and is fine for many non-bearing walls; check local code for bearing walls.
Sources and references
- Chapter 6 Wall Construction, 2021 IRC (ICC)
- Advanced framing for fully sheathed wall systems (APA The Engineered Wood Association)
- Advanced Framing Systems and Packages, Building America Top Innovation (U.S. Department of Energy)
Next steps for this project
The usual order for a framing, decks & fences project. See all framing, decks & fences calculators.
Results are estimates based on standard formulas and typical product specifications. Confirm quantities with your supplier and local code before ordering.