Thermal expansion coefficient converter
0.000012 per kelvin is 12 ppm/K. Switch a linear expansion coefficient α between kelvin, Celsius, Fahrenheit and Rankine forms, as plain reciprocal degrees, parts per million or percent, so US datasheets and SI handbooks share one unit. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Value
- 0.000012
- Source unit
- per_kelvin
- Target unit
- ppm_per_kelvin
- Result
- 12
- From label
- per kelvin (K⁻¹)
- To label
- parts per million per kelvin (ppm/K)
- Factor
- 1,000,000
A thermal expansion coefficient converter turns a linear expansion coefficient α written in one inverse-temperature unit into another without re-deriving Fahrenheit interval factors or counting powers of ten for parts-per-million tables. Identical inputs always produce identical outputs with no network calls, no model sampling, and no clock dependence.
Supported units and the exact inverse-temperature conversion factors
Within the kelvin–Celsius family the engine treats interval size as identical, so α in per kelvin equals α in per Celsius and ppm per kelvin equals ppm per Celsius. Crossing to Fahrenheit or Rankine multiplies or divides by nine fifths because one kelvin interval equals nine fifths of a Fahrenheit (or Rankine) interval; therefore α_K equals α_F times nine fifths and α_F equals α_K times five ninths. Parts per million scale by one millionth relative to pure reciprocal temperature, and percent forms scale by one hundredth.
Absolute temperature conversion, area or volume expansion formulas that need a length and a temperature change, and nonlinear material models are intentionally out of scope so materials scientists, mechanical designers, and students get predictable α-only unit results under one clear convention.
Everyday use in materials and design work
Use the free in-browser thermal expansion coefficient converter when you need a quick per-kelvin to ppm-per-kelvin check, a Fahrenheit reciprocal swap for a US datasheet, or a percent-per-kelvin readout while reading a materials handbook, a finite-element input deck, a piping design note, or a homework problem. Open the page, enter the number and units, and copy the result without installing a spreadsheet, a unit library, or a desktop calculator pack.
Source inputs follow the same retention rules as other KIT parse items, and results are safe to cache because the algorithm is fully deterministic. Authors shipping mobile apps or chatbots can map the result, formula, and factors fields directly into cards that show both the number and the exact interval path engineers and students expect on paper.
What you can do with it
Materials datasheets and handbooks
Convert α from per kelvin or 10⁻⁶/K handbook tables into ppm/K or per Fahrenheit so vendor rows, SI catalogues, and US customary notes share one coefficient unit.
CAD, FEA, and piping inputs
Normalize linear expansion coefficients between 1/K, 1/°C, and 1/°F when merging European and US model decks before a thermal stress or expansion joint run.
FAQ
Is per Celsius the same as per kelvin for α?
Yes for interval-based coefficients. A one-degree Celsius change equals a one-kelvin change in size, so α in °C⁻¹ equals α in K⁻¹. Absolute scale offsets (0 °C ≠ 0 K) do not apply to ΔT-based α units.
How does Fahrenheit conversion work?
One kelvin interval equals 9/5 Fahrenheit intervals, so α_K = α_F × (9/5) and α_F = α_K × (5/9). Rankine uses the same interval size as Fahrenheit. ppm/°F applies the same factor after the 10⁻⁶ scale.
Is the thermal expansion coefficient converter free?
The browser tool runs free on your device.
How do I turn 0.000012 per kelvin into ppm/K?
Multiply by one million: 0.000012 per kelvin becomes 12 ppm/K. Parts per million per kelvin is simply α counted in millionths, the form many handbook tables use for metals and alloys.
Does the converter work out how much a part expands?
No. It only changes the unit of α. Finding a change in length, area or volume needs a size and a temperature change, and that calculation is outside this converter.
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/thermal-expansion-coefficient \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"value":0.000012,"from":"per_kelvin","to":"ppm_per_kelvin"}'const res = await fetch("https://api.kit.forhosting.com/conv/thermal-expansion-coefficient", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"value": 0.000012,
"from": "per_kelvin",
"to": "ppm_per_kelvin"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/thermal-expansion-coefficient",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"value": 0.000012,
"from": "per_kelvin",
"to": "ppm_per_kelvin"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/thermal-expansion-coefficient", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"value":0.000012,"from":"per_kelvin","to":"ppm_per_kelvin"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"value":0.000012,"from":"per_kelvin","to":"ppm_per_kelvin"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/thermal-expansion-coefficient", 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": 0.000012,
"from": "per_kelvin",
"to": "ppm_per_kelvin"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.thermal_expansion_coefficient",
"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 browser tool runs free on your device; the prepaid API charges $0.002 per successful item when pipelines need the same contract from servers and automation.
Supported units and the exact inverse-temperature conversion factors
The converter accepts ten thermal-expansion-coefficient families under stable canonical codes: per_kelvin for reciprocal kelvin (K⁻¹ or 1/K), per_celsius for reciprocal degree Celsius (°C⁻¹), per_fahrenheit for reciprocal degree Fahrenheit (°F⁻¹), per_rankine for reciprocal rankine (R⁻¹), ppm_per_kelvin and ppm_per_celsius for parts per million per kelvin or per Celsius, ppm_per_fahrenheit for parts per million per Fahrenheit degree, micro_per_kelvin for the 10⁻⁶ per kelvin microstrain-style form, and percent_per_kelvin plus percent_per_fahrenheit for percent-per-degree presentations common in some engineering sheets. Friendly aliases such as 1/K, 1/°C, 1/°F, ppm/K, ppm/°F, %/K, µ/K, 1e-6/K, and phrases like per kelvin or parts per million per degree Celsius are normalized case-insensitively so forms and APIs can pass either short codes or full names with spaces, hyphens, or underscores.
Request shape, response fields, and unknown-unit errors
The error message names the bad field and lists the supported set so clients can correct forms without guessing. Negative values are allowed when a dataset encodes contraction conventions that way; zero converts cleanly to zero in every target unit. Send a JSON body with three required fields: value as a finite number, from as the source unit string, and to as the target unit string. Aliases amount, quantity, alpha, and alpha_value are accepted for value; unit_from and source for from; unit_to and target for to. On success the response echoes the canonical from and to codes, human-readable from_label and to_label strings, the converted result, the dimensionless factor from source to target, the intermediate alpha_per_kelvin in reciprocal kelvin, a short formula line suitable for UI display, the method tag thermal_expansion_coefficient_via_per_kelvin, the fixed list of units_supported, and a factors object documenting the Fahrenheit-to-kelvin interval ratio, the ppm and percent multipliers, and the Celsius-equals-kelvin and Rankine-equals-Fahrenheit identities. Missing value, non-finite numbers such as NaN or Infinity, missing unit fields, and unknown unit tokens all fail with invalid_input and are not charged after the engine rejects the request. Identical inputs always yield identical JSON because the path is pure arithmetic with no randomness, no remote lookup, and no dependence on the wall clock, which makes the endpoint safe to pin in continuous-integration goldens and SDK contract tests for material libraries and CAD metadata pipelines.
Browser use, API pricing, and everyday materials and design workflows
Switch to the prepaid API when a materials database, CAD preprocessor, homework checker, or lab notebook must convert expansion coefficients at scale under a stable KIT contract at $0.002 per successful item; validation failures that raise invalid_input do not consume balance after rejection. Pair this endpoint with thermo expansion calculators when a product pipeline also needs ΔL or ΔA from α and ΔT, or call it alone when search traffic is specifically for thermal expansion coefficient unit conversion—1/K, ppm/K, 1/°F, and related forms—rather than a general unit switchboard or a size-change formula.
Integration use cases
Homework and lab notebooks
Convert student α values among ppm/K, percent/K, and reciprocal temperature with exact 9/5 factors, prepaid deterministic API calls, and clear invalid_input on unknown units.
Technical questions
How do I convert thermal expansion coefficient from per kelvin to ppm/K?
Send JSON with value (α in 1/K), from set to per_kelvin (or 1/K), and to set to ppm_per_kelvin (or ppm/K). The result multiplies by 1e6 because 1 ppm/K = 10⁻⁶ K⁻¹.
What happens if I send an unknown unit?
The request fails with invalid_input. The error message names the field and lists supported units such as per_kelvin, ppm_per_kelvin, per_fahrenheit, micro_per_kelvin, and percent_per_kelvin.