ForHosting KIT · Developer Utilities

McNemar's test calculator

McNemar's test asks whether two paired binary classifications disagree in a systematic way.

● BetaFree · in your browser

Use it from WebAPIEmailTelegramApp soon

You observe the same subjects twice—before and after a treatment, two raters scoring the same cases, or two diagnostic tests on the same patients—and you fold those pairs into a 2x2 table. Concordant pairs sit on the diagonal and do not inform the null; only the two discordant cells, conventionally named b and c, enter the chi-square statistic. This calculator accepts the four non-negative integer cell counts of that paired table, rejects a negative count instead of silently clipping it, and returns the McNemar chi-square statistic with one degree of freedom together with the corresponding upper-tail p-value. Continuity correction is on by default, matching the Edwards form used by common statistical packages; you can turn it off to recover the original 1947 ratio of the squared discordant difference over the discordant total. The free browser widget and the API share one isomorphic function, so a homework key and a production script never disagree on the same table. Successful API calls are billed at the published base of $0.002 per item; invalid input is not charged.

How to use it

Enter your values in the form above. The tool checks them before calculating and shows the result on the same page.

Check your inputs

Use the labels and units shown next to each field. If something is missing or outside the allowed range, the page points to the field to fix.

Use it again or automate it

Use the browser tool for individual checks and the API when you need the same capability in an automated workflow.

What you can do with it

Get an answer now

Enter one set of values and see the result without building a spreadsheet or script.

Compare scenarios

Change one value at a time and rerun the calculation to understand what affects the result.

Automate repeated work

Use the API when the same calculation needs to run inside your product or workflow.

FAQ

How do I use this capability?

Complete the fields above and run it on this page. The form highlights anything that needs attention.

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

POSThttps://api.kit.forhosting.com/stat/mcnemars-test

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/stat/mcnemars-test \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"a":59,"b":6,"c":16,"d":80}'

const res = await fetch("https://api.kit.forhosting.com/stat/mcnemars-test", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "a": 59,
    "b": 6,
    "c": 16,
    "d": 80
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/stat/mcnemars-test",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "a": 59,
    "b": 6,
    "c": 16,
    "d": 80
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/stat/mcnemars-test", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"a":59,"b":6,"c":16,"d":80}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"a":59,"b":6,"c":16,"d":80}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/stat/mcnemars-test", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "a": 59,
  "b": 6,
  "c": 16,
  "d": 80
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "stat.mcnemars_test",
  "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

Per request$0.002

Published price — no tokens, no invented credits. A failed task is never charged.

Limits

`max_cell`	10000000
`max_n`	40000000

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.

Read the full KIT documentation →