Linear mass density converter
Turn a weight-per-length figure into the unit your sheet asks for: 1.5 kg/m is 1.007953462709 lb/ft. Eight units used on cable data sheets, rope specs, yarn tickets and coursework, all converted through kilograms per metre. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Value
- 1.5
- From
- kg/m
- To
- lb/ft
- Result
- 1.0079534627 lb/ft
- Converted
- 1.0079534627
- Value kgm
- 1.5
- Factor
- 0.6719689751
A linear mass density converter turns one mass-per-length magnitude into another everyday unit without spreadsheet factors or mental decade tables. Enter a finite value plus a source unit and a target unit among kilograms per metre, grams per metre, grams per centimetre, milligrams per metre, pounds per foot, pounds per yard, ounces per foot, and textile tex; the tool returns the converted linear density, the SI intermediate in kg/m, the exact unit factor applied, and step-by-step substitution lines you can paste into a cable schedule, yarn ticket, or design review. Rope and wire makers quoting pounds per foot, process engineers comparing kilograms per metre cable mass, textile labs reading tex and grams per kilometre, and students converting homework linear density all need the same deterministic path.
Which linear mass-density units are supported and how conversion works
This capability converts among eight everyday linear mass-density units that dominate cable and rope data sheets, textile yarn tickets, pipe and extrusion mass-per-length tables, and undergraduate mechanics coursework. The kilogram per metre (kg/m) is the SI coherent unit of mass per unit length and the internal hub: every conversion multiplies the input by how many kilograms per metre equal one source unit, then divides by how many kilograms per metre equal one target unit.
Grams per metre use the exact SI milli-to-kilo decade of one thousandth of a kilogram per metre and appear on light cordage and laboratory fibre notes. Grams per centimetre equal exactly one tenth of a kilogram per metre because one gram is one thousandth of a kilogram and one centimetre is one hundredth of a metre. Milligrams per metre and textile tex both equal one millionth of a kilogram per metre: one tex is defined as one gram per kilometre, which is the same ratio.
Pounds per foot and pounds per yard use the international avoirdupois pound mass of zero point four five three five nine two three seven kilograms divided by the exact international foot of zero point three zero four eight metres or yard of zero point nine one four four metres. Ounces per foot use one sixteenth of that pound over the same foot. Same-unit requests succeed and return the input magnitude with a short message that no change of unit was required.
Practical tips, limits, and when to use this landing
Prefer sending bare numbers for value when you control the client; string numbers are accepted only when they match a strict finite numeric pattern without currency symbols or thousand separators. Round-trip checks are straightforward: convert A to B and B back to A and confirm you recover the original within the published twelve-decimal rounding.
When teaching, pair classic examples such as one kilogram per metre to one thousand grams per metre, one and a half kilograms per metre into pounds per foot for cable schedules, and one hundred tex into milligrams per metre for yarn linear density (identity under the exact g/km definition). Stay inside the absolute range so intermediate kg/m values cannot overflow.
This landing targets people searching for a linear mass density converter, kg/m to lb/ft, grams per meter to kilograms per meter, or pounds per foot linear density online; it is not a general multi-quantity unit converter, not a volumetric density (kg/m³) tool, not an areal density (kg/m²) calculator, and not a pipe-mass estimator from diameter and wall thickness.
What you can do with it
Cable and rope mass-per-length schedules
Wire and cordage suppliers convert kg/m catalogue values to lb/ft or lb/yd so mixed SI–imperial tenders and installation packs share one linear mass figure.
Textile yarn tickets and lab notes
Spinning and weaving labs convert tex (g/km) to g/m or mg/m for yarn tickets, quality control sheets, and cross-plant data exchange.
Homework and mechanics checks
Students convert kg/m, g/m, and lb/ft linear-density homework values with deterministic steps they can compare against hand calculations before submission.
FAQ
Is tex the same as g/km?
Yes. One tex is defined as one gram per kilometre, which equals exactly 10⁻⁶ kg/m—the same factor as mg/m.
Is the linear mass density converter free?
The browser tool is free and runs locally.
How many pounds per foot is 1.5 kg/m?
1.5 kg/m is 1.007953462709 lb/ft. One pound per foot equals 1.48816394357 kilograms per metre, so the converter divides the kilograms per metre by that factor.
How do grams per centimetre compare with kilograms per metre?
One gram per centimetre is exactly a tenth of a kilogram per metre, because a gram is a thousandth of a kilogram and a centimetre is a hundredth of a metre.
Can I convert a negative linear density?
Yes. Negative values are accepted for signed differences, such as the gap between two cable specifications. The size of the number must stay within one trillion so the result remains a finite figure.
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/linear-density \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"value":1.5,"from":"kg/m","to":"lb/ft"}'const res = await fetch("https://api.kit.forhosting.com/conv/linear-density", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"value": 1.5,
"from": "kg/m",
"to": "lb/ft"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/linear-density",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"value": 1.5,
"from": "kg/m",
"to": "lb/ft"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/linear-density", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"value":1.5,"from":"kg/m","to":"lb/ft"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"value":1.5,"from":"kg/m","to":"lb/ft"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/linear-density", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"value": 1.5,
"from": "kg/m",
"to": "lb/ft"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.linear_density",
"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
Unknown unit names fail with a clear invalid_input error instead of silent wrong factors.
Which linear mass-density units are supported and how conversion works
Common aliases are accepted case-insensitively: kilograms per meter and kg/m for the SI form, grams per metre and g/m, pound per foot and lb/ft or lbm/ft, grams per kilometre and tex, and similar full-word spellings for the rest. If the name is not on that list the solver rejects the request with invalid_input naming the bad field and listing supported units, so clients never guess whether a typo produced a wrong number. Negative values are allowed for signed difference contexts; absolute magnitude must stay within the published one-trillion limit so intermediate products remain finite in IEEE double precision on the Worker and in the browser.
How to call the API and read the response
Value must be a finite number or a strict numeric string within absolute limits of one trillion. Wire this into dashboards, mobile clients, or batch jobs that already hold a linear-density reading and only need a second unit for display, regulatory comparison, or mixed SI–imperial reports without shipping floating conversion tables in every app binary. Send a JSON body with three required fields: value (aliases amount, mu, linear_density, and rho_l), from (aliases from_unit, unit_from, and source), and to (aliases to_unit, unit_to, and target). From and to must resolve to supported unit names after alias normalization. On success the response echoes the rounded input value, canonical from and to labels, result and converted set to the same rounded target magnitude, value_kgm as the SI intermediate in kilograms per metre, unit as the target label, factor as the from-to multiplier, formula as the short equation string, message as an English summary, steps as ordered substitution lines, and supported_units as the eight canonical identifiers. Failed validation—missing fields, non-finite numbers, values outside absolute limits, or an unknown unit name—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, limits, and when to use this landing
Normalize display labels on your side if you need locale-specific spellings—this API always returns the short canonical tokens kg/m, g/m, g/cm, mg/m, lb/ft, lb/yd, oz/ft, and tex so automated tests stay stable. Prefer this capability when both endpoints are among the eight supported mass-per-length units and you need deterministic factors and step strings; if you need bulk density or surface density, use the dedicated converters for those quantities instead. Failed tasks that return invalid_input do not consume prepaid balance, which keeps exploratory scripts cheap when clients deliberately probe unknown unit names.
Technical questions
Which linear mass-density units can I convert?
Kilograms per metre (kg/m), grams per metre (g/m), grams per centimetre (g/cm), milligrams per metre (mg/m), pounds per foot (lb/ft), pounds per yard (lb/yd), ounces per foot (oz/ft), and tex (g/km), including common full-word aliases.
Are pounds mass or force?
Mass. Linear density is mass per length. Aliases accept lb, lbs, and lbm per foot or yard; pound-force (lbf) is not a supported unit name.
What happens if I send an unknown unit name?
The API returns invalid_input, names the bad field, and lists the supported units. The failed task is not charged.