Calculate My Home
Units

Stud Calculator

Enter the wall length and height, spacing and openings to get every stud, plate and header drawn in place with a cut list.

Units
Wall length
ft
in
Wall height
ft
in

Bottom of the bottom plate to the top of the top plate.

Stud spacing
Studs
Top plate
Corners at

Walls that butt into this one.

0 with ladder blocking.

Doors and windows

  • Window 1

    in
    in
    in

    Floor to the rough opening.

    in

Size it for the load

%

Warped and split studs.

2×4 studs to buy, 91 ½ in long

14studs

9 full-height studs, 2 jacks and 4 cripples, plus 10% for waste. Plates: 3 boards of 12 ft.
On layout
7
King studs
2
Jack studs
2
Cripples
4
Corners and T's
0
Stud length
91 ½ in
36 in12 ft8 ft16 in o.c.
  • Studs and king studs
  • Jacks, headers and sills
  • Cripples and plates
The math

  1. Layout studs

    144 in ÷ 16 in = 9 spaces: a stud at each mark plus one at each end = 10 studs

  2. Removed for openings

    layout studs where the openings, kings and jacks go = 3 studs

  3. Cripples

    one on each layout mark above the headers and under the sills = 4 pieces

  4. Openings

    1 × (2 × 1 kings + 2 × 1 jacks) = 4 studs

  5. Corners and T's

    0 × 2 + 0 × 2 = 0 studs

  6. Stud length

    96 in − 3 plates × 1.5 in = 91 ½ in

  7. Studs to buy

    (9 + 2 jacks + 1 for cripples) × 1.1, rounded up = 14 studs

  8. Plates

    3 rows × 144 in, in 12 ft boards = 3 boards

Material list

12 ft × 8 ft wall, 2×4 at 16 in on center, 1 openings.

QuantityItem
14pcs

2×4 studs

Cut to 91 ½ in; jacks and cripples come out of these

3pcs

2×4 plates, 12 ft

1 bottom + 2 top, joints in the two top plates at least 24 in apart

2pcs

2×8 header, opening 1

Cut to 39 in, with a ½ in plywood spacer

1pcs

2×4 rough sills

One flat plate under each window

92nails

16d common nails (3½ in)

Per the IRC fastening schedule, Table R602.3(1)

A 12 ft wall framed at 16 in on center takes 10 studs on layout, one at each end and one on every 16 in mark between. Put a 36 × 48 in window in it and the count becomes 9 full-height studs, 2 jacks and 4 cripples, which with 10% for waste is 14 studs to buy, plus 3 plate boards of 12 ft. At 24 in on center the same bare wall needs 7 studs.

How the studs are counted

Layout starts at one end of the wall. The first stud sits flush with the end, and from there a mark every 16 in (or 24 in) gives the center of the next stud, so sheathing and drywall edges land on wood. A last stud closes the other end. The calculator then works through what the wall needs on top of that layout.

Layout studs = length ÷ spacing, rounded down, + 1, + 1 for the end. Stud length = wall height − 3 plates × 1½ in.

Worked through for the default 12 ft wall: 144 ÷ 16 = 9 spaces, so studs at 0, 16, 32 and so on up to 128 in, plus the end stud: 10 studs. An 8 ft wall with a bottom plate and a double top plate leaves 96 − 4½ = 91½ in for each stud.

Studs for doors and windows

Each opening replaces the layout studs that fall inside it with a frame:

  • King studs run full height beside the opening. IRC Table R602.7.5 sets how many at each end in an exterior wall: 1 up to a 4 ft header, 2 up to 8 ft, 3 up to 14 ft and 4 up to 18 ft where the design wind speed is up to 140 mph (Exposure B).
  • Jack studs (trimmers) stand inside the kings and carry the header. The header span tables give the number, 1 to 3 at each end; the beam span calculator looks it up for your load.
  • Cripples fill the layout marks above the header and, for a window, below the rough sill, so the sheathing stays nailed every 16 in.

In the default wall, the window at 48 in from the left end knocks out 3 layout studs. It gets a king and a jack on each side, a 2-2×8 header 39 in long, and 2 cripples 3¼ in long above it and 2 of 31½ in below the sill. The jacks are 81 in: the sill height plus the rough opening height, less the bottom plate.

Corners and T intersections

A traditional exterior corner uses three studs, the end stud of one wall plus two more so the other wall and the drywall both have something to nail to. Building Science Corporation's advanced framing guide describes the two-stud corner with drywall clips, which leaves room for insulation. A T intersection, where a partition meets the wall, usually gets two extra studs; ladder blocking between two layout studs does the same job with offcuts, so set the extra studs to 0.

A 12 ft wall with three-stud corners at both ends and one T intersection needs 16 full-height studs: 10 on layout, 4 at the corners and 2 at the T.

How many studs for common wall lengths

Bare wall, no openings or corners:

Wall lengthStuds at 16 in o.c.Studs at 24 in o.c.
8 ft75
10 ft96
12 ft107
14 ft128
16 ft139
20 ft1611
24 ft1913

A common shortcut is one stud per foot of wall. For the 12 ft wall with two corners and a T above, that gives 12 studs against the 16 it really takes, so count the corners and openings.

16 or 24 inches on center?

IRC Table R602.3(5) lets 2×4 bearing studs up to 10 ft tall sit at 24 in on center when they carry only a roof and ceiling, and requires 16 in when they carry a floor as well. 2×6 studs may stay at 24 in with one floor above. Non-bearing 2×4 partitions may be 24 in apart and up to 14 ft tall. Siding, drywall thickness and cabinet backing may still call for 16 in.

Plates, headers and nails

Walls get a single bottom plate and a double top plate. IRC R602.3.2 asks for the joints in the two top plates to be offset at least 24 in and for the upper plate to lap at corners. The calculator counts plate boards per row at the stock length you pick. Nails follow IRC Table R602.3(1): two 16d commons through the plate into each stud end, three into each end of a header, and plate-to-plate nails every 16 in.

Next steps