Wheel torque calculator
250 N·m from the engine in a 3.5 first gear with a 3.73 final drive becomes 3263.75 N·m at the driven axle, through an overall ratio of 13.055. Enter engine torque, gear ratio and final drive to compare gears and differentials. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Engine torque
- 250
- Gear ratio
- 3.5
- Final drive
- 3.73
- Overall ratio
- 13.055
- Wheel torque
- 3,263.75
- Torque unit
- nm
- Torque unit label
- N·m
Builders, tuners, and powertrain engineers often need the torque available at the drive wheels for a given engine torque in a specific gear—before a gear-ratio swap, when comparing differentials, or when filling a launch-torque table. This wheel torque from engine torque calculator multiplies crankshaft torque by the transmission gear ratio and the final drive ratio, returning overall ratio and wheel torque in the same unit you supply. It deliberately ignores drivetrain losses so the result is the ideal geometric multiplication used in textbooks and parts catalogs, not a lossy chassis-dyno estimate.
How wheel torque follows from engine torque and the gear train
An internal-combustion or electric motor produces torque at the crankshaft or output shaft. The selected transmission gear multiplies that torque by the gear ratio: a first gear of 3.5 multiplies crank torque by 3.5 while dividing rotational speed by the same factor. The differential multiplies torque again by the final drive (axle) ratio, so the overall ratio from crankshaft to the axle shafts is gear ratio times final drive.
Ideal wheel or axle torque is therefore engine torque times that overall product. Negative engine torque is accepted so you can model engine braking as a signed quantity; gear ratio and final drive must be strictly positive because a non-positive ratio would not describe a physical gear mesh. The result is total torque at the driven axle for the stated ratios—not a per-wheel split under an open differential, and not a tractive force until you divide by tire radius.
Use it as the ideal upper bound before applying an efficiency factor of your own if you need a lossy estimate.
Where a wheel torque calculator earns its keep
Performance shops compare candidate gear sets and final drives against peak engine torque before ordering parts, using this calculator as a deterministic oracle instead of a fragile notebook formula. Track-day and launch-control tooling estimates peak axle torque in first gear for traction budgeting when tire radius and grip data are handled separately. Fleet and OEM documentation generators fill tables of ideal axle torque per gear for every powertrain SKU without embedding multiplication bugs.
What you can do with it
Gear and differential selection
Compare ideal axle torque in each gear after a transmission or final-drive swap using peak or rated engine torque from the dyno sheet.
Launch and traction budgets
Estimate first-gear wheel torque for launch-control and tire-grip calculations before applying radius and efficiency factors of your own.
FAQ
Which torque unit should I use?
Use nm (N·m, default), lbft (lbf·ft), or lbfin (lbf·in). The unit is a label only; input and output share the same unit with no conversion.
Does this include drivetrain losses or per-wheel split?
No. The result is ideal total axle torque for the stated ratios. Apply your own efficiency factor or divide by drive-wheel count if you need a lossy or per-wheel estimate.
Why can I enter a negative engine torque?
So you can model engine braking. A negative value at the crankshaft becomes a negative value at the axle, multiplied by the same ratios. Gear ratio and final drive, however, must always be positive.
How do I turn wheel torque into a pushing force at the road?
Divide it by the tire radius. The result here is total torque at the driven axle, not a tractive force, so the radius step comes afterwards, with your own tire data.
How is the overall ratio worked out?
It is the gear ratio times the final drive. A 3.5 first gear with a 3.73 final drive gives 13.055, so the engine's torque is multiplied 13.055 times on its way to the axle.
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/travel/wheel-torque \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"engine_torque":250,"gear_ratio":3.5,"final_drive":3.73}'const res = await fetch("https://api.kit.forhosting.com/travel/wheel-torque", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"engine_torque": 250,
"gear_ratio": 3.5,
"final_drive": 3.73
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/travel/wheel-torque",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"engine_torque": 250,
"gear_ratio": 3.5,
"final_drive": 3.73
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/travel/wheel-torque", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"engine_torque":250,"gear_ratio":3.5,"final_drive":3.73}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"engine_torque":250,"gear_ratio":3.5,"final_drive":3.73}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/travel/wheel-torque", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"engine_torque": 250,
"gear_ratio": 3.5,
"final_drive": 3.73
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "travel.wheel_torque",
"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 same pure logic powers the free browser tool and the API path, so workshop notes and automation scripts always agree on the arithmetic.
How wheel torque follows from engine torque and the gear train
This capability uses exactly that product and sets losses_model to none, matching the common design estimate that ignores gearbox, differential, and bearing friction.
Input fields, units, and the response contract
Optional precision (integer 0–12, default 6) controls decimal places on rounded fields for stable goldens and UI display. Example: 250 N·m engine torque, gear ratio 3.5, and final drive 3.73 yields overall ratio 13.055 and wheel torque 3263.75 N·m. Send a JSON body with three required finite numbers: engine_torque (crankshaft torque in your chosen unit; zero and negative values are allowed), gear_ratio (transmission ratio for the gear of interest, strictly positive), and final_drive (differential or axle ratio, strictly positive). Optional torque_unit accepts nm for newton-metres (default), lbft for pound-force feet, or lbfin for pound-force inches; the unit is a label only—there is no conversion—so wheel_torque is returned in the same unit as engine_torque. On success the response echoes the inputs, reports overall_ratio as gear_ratio times final_drive, returns wheel_torque, and includes formula, method, and losses_model strings. Missing fields, non-finite values, zero or negative ratios, and unknown torque units fail with invalid_input and are not billed. Aliases such as torque, gr, fd, and unit work when integrating with existing forms.
Where a wheel torque calculator earns its keep
Keep requests small, pin the rounded wheel_torque in tests, and you get reproducible gear-train torque checks for builders, educators, and edge workers without standing up a full vehicle-dynamics simulator of your own.
Integration use cases
Powertrain tables and documentation
Fill per-gear wheel-torque columns in OEM or aftermarket catalogs with a deterministic API that matches the free browser widget.
Technical questions
How do I calculate wheel torque from engine torque?
Provide engine_torque, gear_ratio, and final_drive. Wheel torque is engine_torque × gear_ratio × final_drive. Losses are ignored (ideal 100% efficiency).
What is overall ratio?
Overall ratio is gear_ratio times final_drive—the total speed reduction and torque multiplication from crankshaft to the driven axle.
What does the wheel torque calculator cost?
The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.