Stud calculator
This lays a wall out and counts sticks — field studs at your spacing, plus the extras you enter and the plate runs. It says nothing about whether a wall bears a load or what size the studs must be; that is a design question for your plans or an engineer. Confirm the layout against the actual opening before you cut.
Enter the wall length and the stud spacing and the tool works out the field studs, then adds whatever you tell it for corners and openings and totals the plate stock. The field count is the wall length divided by the spacing, rounded up, plus one to close the end.
Exemple détaillé
A 16-foot wall at 16-inch centres is 192 ÷ 16 = 12 spaces, so 13 field studs. Add, say, 5 for two corners and a door and you are at 18 studs. The plates are a double top plate plus a bottom plate over 16 feet: 3 × 16 = 48 linear feet of plate stock.
In metric: a 4.8 m wall at 400 mm centres is 4,800 ÷ 400 = 12 bays, so 13 field studs; the same 5 extras make 18, and three plate runs over 4.8 m is 14.4 linear metres.
Sur le chantier
Framing out a basement. Four walls — two at 30 ft, two at 24 ft — at 16 in centres. A 30 ft wall is 360 ÷ 16 = 22.5, so 23 bays and 24 studs; a 24 ft wall is 288 ÷ 16 = 18 bays, 19 studs. Field studs: 2 × 24 + 2 × 19 = 86. Four corners at three studs each is 12, two doors at two kings, two jacks and a couple of cripples is 12 more. 110 studs, and the lumberyard bundle is usually a round number, so call it 112. Plates: 108 ft of wall × 3 runs = 324 lin ft — in 16-footers that is 20.25, so 21 pieces, and you will pick lengths so the top-plate breaks land on a stud. (The same 30 ft wall in metric is 9.14 m: 9,140 ÷ 400 = 22.85, so 23 bays and 24 studs.)
The wall that is not a whole number of bays. A 13 ft 4 in wall is 160 in, which is exactly 10 bays at 16 — 11 studs, no short bay. A 14 ft wall is 168 in: 10.5 bays, so 11 bays and 12 studs, with the last bay 8 in wide. The tool rounds the bay up because the sheathing needs something to land on at the end; the stub bay is normal, not an error.
Precut studs. The yard sells studs at 92⅝ in (2,353 mm) for an 8 ft wall: 92⅝ plus three 1½ in plates comes to 97⅛ in, which with the ceiling board and the floor leaves an 8 ft finished ceiling. That is a mill convention, not a rule — the plans set the wall height, and a 9 ft wall wants the 104⅝ stud (2,657 mm).
What went wrong?
Quick referencefor framing
- Field studs
- (wall in inches ÷ spacing), rounded up, + 1
- At 16 in o.c.
- 8 ft = 7 studs · 12 ft = 10 · 16 ft = 13 · 20 ft = 16 · 24 ft = 19
- At 24 in o.c.
- 8 ft = 5 studs · 12 ft = 7 · 16 ft = 9 · 20 ft = 11 · 24 ft = 13
- Plates
- wall length × 3 for a double top plate; break the top plates on a stud
- Precut stud lengths (mill convention)
- 92⅝ in → 8 ft wall · 104⅝ → 9 ft · 116⅝ → 10 ft (2,353 · 2,657 · 2,962 mm)
- Metric spacing
- 400 mm ≈ 16 in · 600 mm ≈ 24 in · 2,400 mm wall at 400 = 7 studs · 4,800 mm at 400 = 13 · at 600 = 9
Waste & overagewhat to add, and why
- Framers buy a handful of studs beyond the count — one or two per wall for the twisted ones, plus the cripples and blocking that get cut from full lengths. There is no waste field here, so add them to the extra-studs field or to the order.
- Plates are bought in long lengths and cut; a 24 ft wall takes two 12 ft plates per row, and the joints must land on a stud, so buy one extra length per wall for the joint offsets.
Mistakes to catchbefore you order
- Forgetting the end stud: a 16 ft wall at 16 in centres is 12 bays and 13 studs, before corners and openings.
- Typing the on-centre spacing in feet (1.33) into a field set to inches, or 16 into a metric field (16 mm).
- Leaving the extra-studs field at 0 on a wall with a door and two corners; the tool cannot see your layout, so those come from you.
What an inspector looks forthe building inspector, at the framing call
On this part of the job
- Stud spacing measured along a wall, not taken from the layout marks — a wall that started at the right spacing can drift by the far end.
- Plates: the number of top plates, how the laps are made at corners and intersections, and that no splice lands where the drawing forbids it.
- Blocking and backing where it has to be: fire blocking in the cavity, and solid backing behind anything that will be screwed to the wall later.
- Bearing walls carried down through the floors, and that a wall the drawing calls bearing has not been framed as a partition.
- Notches and holes in studs — size and position against the limits in the code, especially where plumbing or a duct has been through.
Have this ready
- The framing plan with the wall types marked.
- The spacing you laid out to, and a tape long enough to check it in one pull.
- Fire blocking already in before the call, because it is the item that sends crews back up the ladder.
Every figure an inspector measures against comes from the code your jurisdiction has adopted, the stamped drawing, or the manufacturer's printed instructions — so none of them are printed here. Look the number up in your own book, type it into the tool, and the arithmetic is yours.
La formule
studs = ⌈length ÷ spacing⌉ + 1 + extras · plate = length × (1 + top plates)
Dividing the length by the spacing gives the number of bays; rounding up covers a partial last bay, and the plus one is the stud that finishes the wall. Plates simply run the length once for the bottom and once for each top plate you set.
Questions
- How many studs do I need for a wall?
- Divide the wall length by the stud spacing, round up, and add one for the stud that closes the far end. A 16-foot wall at 16-inch centres is 192 ÷ 16 = 12 spaces, so 13 studs before you add anything for corners and openings. In metric, a 4.8 m wall at 400 mm centres is 4,800 ÷ 400 = 12 spaces, 13 studs. This tool does that and lets you add the extras.
- What spacing should studs be at?
- Sixteen inches on centre is the common default and what this tool starts with; nineteen-point-two and twenty-four inch layouts are also used. In metric the tool starts at 400 mm, with 600 mm the other common layout. Enter whatever your plans call for — the field is editable, and the count follows the number you type rather than assuming one for you.
- How many extra studs for corners and openings?
- A plain corner takes two or three studs, a partition tee adds one, and every door and window wants a pair of jacks and kings plus cripples above and below. Count those from your layout and put the total in the extras field — this tool spaces the field studs and adds your extras on top.
- How much plate material do I need?
- Plates run the full length of the wall, once for the bottom and once for each top plate. A double top plate over a 16-foot wall is 16 + 16 + 16 = 48 linear feet (4.8 m of wall is 14.4 linear metres). Set the number of top plates and the tool totals the plate stock for you.
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