Motor efficiency calculator
Electric motor efficiency is the share of electrical input power that a machine actually turns into useful mechanical power at the shaft, almost always written as a percentage.
Run — free
At a given speed and load you need two consistent power readings: the shaft output P_out from a brake, dynamometer, or rated mechanical kilowatts, and the electrical input P_in absorbed at the terminals. Their ratio is η = P_out / P_in; multiplying by one hundred gives the percent used on nameplates, IEEE 112 and IEC 60034 test sheets, and plant dashboards. This motor efficiency calculator takes those two numbers, rejects a zero electrical input that would divide by zero, and returns the percent, the dimensionless fraction, conversion losses, and a first-law flag when output exceeds input. The free browser runner and the API share one pure function, so homework checks and automation never disagree.
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
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/eng/motor-efficiency \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"mechanical_output":800,"electrical_input":1000}'const res = await fetch("https://api.kit.forhosting.com/eng/motor-efficiency", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"mechanical_output": 800,
"electrical_input": 1000
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/eng/motor-efficiency",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"mechanical_output": 800,
"electrical_input": 1000
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/eng/motor-efficiency", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"mechanical_output":800,"electrical_input":1000}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"mechanical_output":800,"electrical_input":1000}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/eng/motor-efficiency", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"mechanical_output": 800,
"electrical_input": 1000
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "eng.motor_efficiency",
"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.
Limits
max_abs_power | 1000000000000000 |
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. |