HP to kW converter
100 hp is 74.569987158227 kW: type the horsepower from an engine, pump or motor nameplate and get kilowatts with the exact factor, plus the watts, ready for datasheets and reports. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Hp
- 100
- Kw
- 74.5699871582 kW
- Factor
- 0.7456998716
- Watts
- 74,569.987158227
Need a precise horsepower to kilowatts converter for engine specs, motor nameplates, generator ratings or lab worksheets? Enter a non-negative mechanical horsepower value and get the equivalent power in kilowatts using the exact SI factor derived from 550 foot-pounds-force per second.
What this HP to kW converter calculates
This tool converts mechanical horsepower into kilowatts, the SI unit of power used on modern datasheets, grid studies and efficiency calculations. Mechanical horsepower is the classical British engineering unit defined as exactly five hundred fifty foot-pounds-force per second.
Combined with the exact metre and the standard pound-force in newtons, that definition yields seven hundred forty-five point six nine nine eight seven one five eight two two seven zero two watts per horsepower, or zero point seven four five six nine nine eight seven one five eight two two seven zero two kilowatts per horsepower. The converter multiplies your input by that constant and returns kilowatts, the intermediate wattage, and the factor itself so auditors can recompute every step.
It targets the mechanical horsepower common on engines, pumps and industrial motors—not metric horsepower (PS or CV), not boiler horsepower, and not the rounded seven-hundred-forty-six-watt electrical convention—because “hp to kw” search intent almost always means engine and machine ratings in the imperial mechanical sense. Zero is accepted as a valid idle or baseline reading; negative values are rejected as invalid input rather than silently flipped.
How to get an exact kilowatt figure
In the browser, type the horsepower rating and convert instantly with the identical pure function used on the server—no account required for interactive checks, classroom demos or a quick nameplate translation. A successful response includes hp, kw, unit set to kW, the factor, and watts for double-entry audits. Keep the unit meaning explicit in your docs: mechanical horsepower in, kilowatts out.
Status is beta while the public surface stabilizes, but the arithmetic follows fixed SI definitions and will not change for the same inputs. Prefer this dedicated landing when searchers want “hp to kw” rather than a multi-unit Swiss-army converter: the form, title and examples stay focused on the conversion people actually type into the address bar.
What you can do with it
Engine and motor nameplates
Translate imperial horsepower on pumps, compressors and vehicle engines into kilowatts for SI datasheets, procurement and efficiency reports.
Generator and plant sizing
Convert prime-mover horsepower to kilowatts before comparing against electrical load schedules and transformer capacity.
Homework, labs and documentation
Produce exact HP to kW figures for thermodynamics exercises, lab notebooks and customer-facing specification sheets without rounded rules of thumb.
FAQ
Is this metric horsepower (PS/CV) or electrical horsepower?
Mechanical (imperial) horsepower only. Metric PS is 0.73549875 kW exactly; electrical horsepower is often rounded to 0.746 kW. This tool does not use those conventions.
How many kilowatts is 100 hp?
100 mechanical horsepower is 74.569987158227 kW, which is 74,569.98715822703 watts. The converter shows both figures, so you can check the kilowatt value against the wattage.
Where does the factor 0.7456998715822702 come from?
One mechanical horsepower is defined as exactly 550 foot-pounds-force per second. With one foot equal to 0.3048 metres and one pound-force equal to 4.4482216152605 newtons, that works out to 745.69987158227 watts.
Why not just multiply horsepower by three quarters?
Rules of thumb are fine for a napkin estimate, but they drift when you size cabling, compare nameplates from different markets or try to reproduce a colleague's spreadsheet. The exact factor gives the same figure every time.
Can I convert zero horsepower?
Yes. Zero is accepted as a valid idle or baseline reading and gives zero kilowatts. Negative values are rejected instead of being silently flipped to positive.
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/conv/hp-to-kw \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"hp":100}'const res = await fetch("https://api.kit.forhosting.com/conv/hp-to-kw", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"hp": 100
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/hp-to-kw",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"hp": 100
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/hp-to-kw", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"hp":100}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"hp":100}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/hp-to-kw", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"hp": 100
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.hp_to_kw",
"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
Run it free online or call the same pure function through the API at $0.002 per successful request when you need scripted bulk checks and signed results.
How the exact factor works and why it matters
Approximate rules of thumb such as “multiply by three quarters” or “use zero point seven four six” are fine for napkin estimates, but they drift when you size cabling, compare nameplates across markets, or reproduce a colleague’s spreadsheet. Here the factor is fixed from base units: one foot equals zero point three zero four eight metres exactly, one pound-force equals four point four four eight two two one six one five two six zero five newtons from standard gravity and the avoirdupois pound, and five hundred fifty of those foot-pounds-force per second define one mechanical horsepower. There is no network call, no language model, no Date dependency and no random seed: the same horsepower always yields the same JSON. Invalid requests—missing hp, non-finite values, or negative power—fail with invalid_input and are not billed, because the fault is in the client payload rather than in the service.
Using the free widget, API pricing and delivery
For automation, send a JSON body with the field hp as a non-negative finite number; aliases value and horsepower are accepted so older forms and spreadsheets map without renaming columns. Hosted API pricing is a flat $0.002 per successful conversion; validation errors do not consume balance. Integrate one task per rating in a catalog import, or batch from a script that already speaks the KIT task API, webhooks and signed result links.
Technical questions
What conversion factor does this use?
Exact mechanical horsepower: 1 hp = 0.7456998715822702 kW (745.6998715822702 W), from 550 ft·lbf/s and SI base units.
How much does the HP to kW API cost?
Each successful API call costs $0.002. The same converter runs free in your browser with no account required.
What inputs are rejected?
Missing hp, non-finite values (NaN or Infinity), and negative horsepower return invalid_input and are not charged.
Is the result deterministic?
Yes. Pure multiplication by a fixed factor with stable rounding—no network, randomness or clock—so the same input always yields the same JSON.