Wall stud calculator
A 120-inch wall framed at 16 inches on center takes 9 studs, counting both corners, and one door adds 2 more for 11 in total. Keep the length and the spacing in the same unit. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Wall length
- 120
- On-center
- 16
- Number of rough openings
- 1
- Studs per opening
- 2
- Full bays
- 7
- Remainder
- 8
- Base studs
- 9
Framing a partition or exterior wall starts with a cut-list question: how many studs should you order? This wall stud count calculator answers with a deterministic on-center formula. You provide the wall length and the stud spacing in the same linear units—commonly sixteen or twenty-four inches on center—and optionally how many rough openings (doors and windows) need extra king or jack framing. The engine places studs at both ends (the corners), fills intermediate positions on the spacing grid, and adds a configurable number of extra studs per opening so your material list matches field practice. Zero or negative spacing is rejected with a clear invalid input error, which keeps checkout forms and estimating tools honest before lumber is reserved.
Measure wall length and choose a consistent on-center spacing
Measure the plate length of the wall you are framing, end to end, in whatever linear unit your plans use. Stud spacing is the on-center (OC) distance between successive studs—sixteen inches OC and twenty-four inches OC are the residential defaults in many codes, but the calculator accepts any strictly positive finite spacing in the same units as the length. If you measured the wall in inches, send spacing in inches (for example one hundred twenty for a ten-foot run and sixteen for standard OC).
If you work in millimetres or feet, keep both fields in that system; the engine does not convert units, so mixing feet for length with inches for spacing will invent a nonsense stud count.
What you can do with it
DIY partition and remodel framing
Homeowners enter plate length and sixteen-inch OC spacing, add door openings, and know how many studs to load before the weekend build.
Contractor takeoff and bid automation
Estimating tools batch wall runs from floor plans, apply an openings policy, and emit stud counts for purchase orders without spreadsheets.
FAQ
How does the wall stud calculator count studs?
Exact multiples use length/spacing + 1; partial bays still count the far end stud.
What units should I use?
Any consistent linear system. Mixing feet and inches without converting will produce a wrong count.
What if spacing is zero or negative?
Stud spacing and wall length must both be strictly positive; zero or negative values are rejected and not charged.
Is the wall stud calculator free?
The browser tool runs free on your device.
How should I count doors and windows?
Set openings to the number of rough openings that need extra framing members. Raise it if your standard also counts jack studs per opening.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/home/wall-studs \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"wall_length":120,"stud_spacing":16}'const res = await fetch("https://api.kit.forhosting.com/home/wall-studs", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"wall_length": 120,
"stud_spacing": 16
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/home/wall-studs",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"wall_length": 120,
"stud_spacing": 16
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/home/wall-studs", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"wall_length":120,"stud_spacing":16}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"wall_length":120,"stud_spacing":16}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/home/wall-studs", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"wall_length": 120,
"stud_spacing": 16
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "home.wall_studs",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
The browser tool runs free on your device; the prepaid API charges $0.002 per successful item when apps and SDKs need the same contract.
Measure wall length and choose a consistent on-center spacing
Send that value as wall_length; aliases length, wall and span are accepted for form labels that prefer those names. Both fields must be strictly positive finite numbers: zero, negative or non-numeric values raise invalid_input and are not charged. Extremely small or huge values outside the published stability range are also rejected so floating-point bay math stays meaningful on a Worker isolate. Optional aliases for spacing include spacing, oc, on_center and centers, which cover common takeoff spreadsheet column headers.
How corner studs, OC bays, and openings are counted
When the wall length is an exact multiple of the spacing, the formula is simply length divided by spacing plus one. When a partial bay remains at the far end, the engine still counts the closing end stud, which is equivalent to floor(length divided by spacing) plus two. The base layout always includes a stud at each end of the wall—the corners—then places intermediate studs every stud_spacing along the plate. That yields full_bays, remainder (zero when the end lands on grid), and base_studs. Openings are optional: openings defaults to zero and accepts a non-negative integer count of doors and windows that need extra framing members beside the OC layout. studs_per_opening defaults to two—typical for one king stud each side of a rough opening—and may be raised when your shop standard also counts jack studs or lowered when openings are already handled in another takeoff line. opening_studs equals openings times studs_per_opening; studs_needed is the sum of base_studs and opening_studs. The method label is always oc_ends_plus_openings for stable downstream branching. Negative openings, non-integer counts, missing required length or spacing, and zero or negative spacing fail with invalid_input. Identical inputs always produce identical JSON because the path is pure arithmetic with no network, random seed or wall clock.
API usage, pricing, framing workflows, and practical limits
Call the free in-browser wall stud calculator for quick site estimates, lumber-yard kiosks and contractor whiteboards without installing a spreadsheet. Send a JSON body with wall_length and stud_spacing, plus optional openings and studs_per_opening when defaults do not match your standard. Use the prepaid API when a renovation app, quantity-takeoff pipeline, modular home configurator or property-management tool needs a stable contract under KIT balance at $0.002 per successful item; validation failures never consume balance after the engine rejects the request. Pair this endpoint with unit converters when customers mix imperial plans with metric stock lists, or with room dimension helpers when length arrives as separate start and end coordinates that you subtract client-side before calling. Remember that shared corners between perpendicular walls may share a stud in the field—if your material list already deduplicates corners, adjust openings or post-process studs_needed rather than double-counting. Authors shipping SDKs can map studs_needed straight into purchase orders while showing base_studs, opening_studs, full_bays and remainder as explanatory detail for the estimator.
Integration use cases
Lumber yard and ecommerce cut-list tools
Retail sites compute stud counts as shoppers change wall length or OC options, using the same deterministic API contract for quotes and carts.