Foot-pounds to newton-meters converter
Turn a foot-pound torque or work figure into SI newton-meters with the full exact constant: 10 ft·lbf is about 13.56 N·m, with no truncated shortcut creeping into long tables. Handy for wrench charts and datasheets. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Value in foot-pounds
- 1
- Result
- 1.3558179483 N·m
- Converted
- 1.3558179483
- Newton meters
- 1.3558179483
- From unit
- ft·lbf
A foot-pounds-to-newton-meters converter turns a US customary foot-pound force reading into the SI newton-metre value used in modern torque specs, mechanics textbooks, and international engineering datasheets. Approximate mental shortcuts such as one point three five six newton-meters per foot-pound are rejected in favour of the full exact constant, so homework checks and lab exports match standard conversion tables.
Why foot-pounds and newton-meters meet at 1.3558179483314004
The newton-metre is the SI coherent unit of torque and of work: one newton of force through one metre of lever arm, and the common reporting unit for fastener torque, moment of force, and energy in modern science. The foot-pound force remains common in US customary mechanics, North American tool and fastener torque charts, older ballistics and impact notes, and many engineering handbooks that still quote ft·lbf rather than N·m.
The bridge between them is exact for the international definitions: one foot is exactly zero point three zero four eight metres, and the pound-force is defined from standard gravity acting on the international pound-mass, which yields one foot-pound force equal to one point three five five eight one seven nine four eight three three one four zero zero four newton-meters. That makes the conversion a single exact multiplication, newton-meters equals foot-pounds times that constant.
Teachers can contrast the exact path with a rough one-point-three-five-six rule of thumb so students see the small relative error that accumulates on large torque or impact figures when the truncated constant is reused row after row.
Practical tips, checks, and related searches
Round-trip sanity checks are easy: convert one foot-pound and confirm you receive about one point three five five eight one seven nine four eight three three one four zero zero four newton-meters after rounding, or convert ten foot-pounds and confirm about thirteen point five five eight one seven nine four eight three three one four newton-meters. If your source table quotes inch-pounds or kilonewton-metres, scale to foot-pounds or interpret the SI result carefully before treating it as N·m from ft·lbf alone.
Stay inside the absolute range so the product cannot overflow into a non-finite result the solver must reject. When teaching unit analysis, pair a torque example such as a one-pound-force at a one-foot lever arm with the pure conversion so students see that one foot-pound is larger than one newton-metre and that the same exact constant appears in both SI and US customary worksheets.
This landing targets people searching for foot-pounds to newton-meters, convert ft-lbf to N·m, or an exact foot-pound to newton-metre calculator; it is not a multi-unit torque hub, not a newton-meters-to-foot-pounds primary form, not a joules-only energy landing, and not a kinetic-energy or power calculator. Prefer this capability when the input is already in foot-pounds and you only need newton-meters; if you must convert among many torque units in one call, use a broader torque unit converter instead.
What you can do with it
Fastener and tool torque charts
Convert US customary torque specs in ft·lbf into N·m for SI datasheets, metric tool settings, and international assembly instructions with the same exact factor every row.
FAQ
Is this torque or energy?
Foot-pound and newton-metre can name either a moment of force (torque) or energy (work). This tool applies the exact unit factor between ft·lbf and N·m; interpret the physical quantity from your problem context.
Why not use 1.356 N·m per foot-pound?
1.356 is a rounded rule of thumb. This converter hard-codes the exact international constant 1.3558179483314004 N·m per ft·lbf used in precise tables and unit-conversion references.
Is the foot-pounds to newton-meters converter free?
The browser tool is free and runs locally.
How many newton-meters are in one foot-pound?
Exactly 1.3558179483314004 newton-meters, which the converter shows as 1.355817948331 after rounding. The constant follows from the international foot and from the pound-force defined by standard gravity acting on the international pound.
Is a foot-pound bigger than a newton-meter?
Yes. One foot-pound is about 1.356 newton-meters, so the newton-meter figure is always the larger number. If a converted torque spec comes out smaller than the original, the conversion ran in the wrong direction.
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/foot-pounds-to-newton-meters \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"foot_pounds":1}'const res = await fetch("https://api.kit.forhosting.com/conv/foot-pounds-to-newton-meters", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"foot_pounds": 1
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/foot-pounds-to-newton-meters",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"foot_pounds": 1
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/foot-pounds-to-newton-meters", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"foot_pounds":1}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"foot_pounds":1}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/foot-pounds-to-newton-meters", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"foot_pounds": 1
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.foot_pounds_to_newton_meters",
"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 | 1000000000000 |
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
Invalid or missing input fails with a clear invalid_input error instead of inventing a number.
How to call the API and what comes back
Absolute values must stay within the published limit of one trillion. Prefer bare numbers when you control the client; string numbers are accepted only when they match a strict finite numeric pattern without unit suffixes or thousand separators. Send a JSON body with one required finite number field named foot_pounds. Aliases ft_lbf, ft_lb, ftlbf, value, ftlb, and pounds are accepted so SDK clients and form posts can use the name that fits the product. On success the response echoes rounded foot_pounds, sets newton_meters, result, and converted to the same rounded newton-metre magnitude, unit to the token N·m, from_unit to ft·lbf and to_unit to N·m, factor to the rounded multiplier one point three five five eight one seven nine four eight three three one four zero zero four, newton_meters_per_foot_pound to that same exact constant, formula to the string newton_meters equals foot_pounds times that constant, message to a short English summary, and steps to an ordered array of substitution lines. Failed validation—missing fields, non-finite numbers, bare plus or minus signs, non-numeric strings, values outside absolute limits, or a non-finite converted result—returns invalid_input and is never charged. Pricing is a flat $0.002 per successful request with unit item and zero marginal unit price.
Practical tips, checks, and related searches
Failed tasks that return invalid_input do not consume prepaid balance, which keeps exploratory scripts cheap when learners deliberately omit foot_pounds or pass text.
Integration use cases
Homework and exam checks
Students convert classroom foot-pound readings to newton-meters and compare hand work against deterministic steps before submitting worksheets or coding kata fixtures.
Engineering unit alignment
Process notes that mix foot-pounds and newton-meters can be normalized for SI exports, control logic, and API payloads without fragile hand-typed factor tables.
Technical questions
How many newton-meters are in one foot-pound?
Exactly 1.3558179483314004 N·m by international definition: newton_meters = foot_pounds × 1.3558179483314004.
What happens on invalid input?
Missing fields, non-finite values, non-numeric strings, or values outside the absolute limits return invalid_input and are never charged.