Thermal conductivity converter
1 W/(m·K) is 0.5777893165 BTU/(h·ft·°F). Move a material's conductivity between SI datasheets, older US insulation literature and CGS calorie tables, always through the same fixed factors, so a hand calculator never drifts. Free in your browser.
- Free
- Runs in your browser
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- Your data stays on your device
Run — free
Worked example
- Value
- 1
- Source unit of 'value'
- W_m_K
- To
- BTU_h_ft_F
- Result
- 0.5777893165
- From label
- watts per meter-kelvin
- To label
- BTU per hour foot Fahrenheit
- Value wmk
- 1
This thermal conductivity converter turns a numeric conductivity from one common engineering unit into another and returns the converted magnitude with canonical unit labels. Conversion always bridges through watts per meter-kelvin using fixed international SI factors, so the same input always yields the same result with no network calls, no sampling, and no date-dependent shortcuts. Typical checks include one watt per meter-kelvin to BTU per hour foot Fahrenheit, one calorie per second centimeter Celsius to SI, and imperial insulation specs into metric tables.
What the thermal conductivity converter returns and which units it understands
A thermal conductivity conversion answers a narrow question: given a magnitude in one unit, what is the equivalent magnitude in another unit that people actually use for solids, fluids, insulation, and heat-transfer design. This calculator accepts a numeric value, a source unit, and a target unit, then returns the converted result rounded to a stable precision, the canonical from and to identifiers, human-readable labels, the intermediate value in watts per meter-kelvin, and the SI factors used for the bridge.
Canonical ids are W_m_K for watts per meter-kelvin, BTU_h_ft_F for BTU per hour foot Fahrenheit, and cal_s_cm_C for calories per second centimeter Celsius. Everyday spellings such as W/(m·K), W/m·K, watt per meter-kelvin, watts per metre-kelvin, BTU/(h·ft·°F), Btu/h·ft·F, cal/(s·cm·°C), and calorie per second centimeter Celsius normalize to those ids so forms, query strings, and spreadsheets can reuse the same contract without inventing private enums.
Where thermal conductivity conversion fits in materials, buildings, and software
Material datasheets often quote metals and polymers in watts per meter-kelvin while older US HVAC and insulation literature still uses BTU per hour foot Fahrenheit, so a single deterministic converter prevents hand-calculator drift when a technician, designer, or student compares heat-transfer properties. CGS-era tables and some chemistry references still list calories per second centimeter Celsius for pure substances; aerospace and process notes may mix imperial and SI in the same package.
Teachers assign homework that needs a fast, offline check of SI to BTU conductivity without trusting opaque apps that silently change precision. Developers call the same contract from scripts to seed deterministic test vectors for product UIs, to normalize user-entered conductivities before sizing demos, or to satisfy programming-challenge statements that demand exact factors rather than a hand-waved estimate. Product tools use the rewrite when a learner or agent types one BTU per hour foot Fahrenheit and the UI must show watts per meter-kelvin and cal-scale values side by side.
Pair it with heat-transfer and materials calculators when you already have conductivity and need flux or resistance next, and with the general multi-category unit converter when the same form must also handle length or temperature.
What you can do with it
Material and insulation datasheets
Convert between W/(m·K) and BTU/(h·ft·°F) when comparing metals, polymers, and building insulation specs across SI and imperial catalogs.
CGS chemistry tables to SI
Normalize cal/(s·cm·°C) literature values into watts per meter-kelvin for deterministic process models and modern documentation.
FAQ
What does the thermal conductivity converter cost?
It is free in your browser on this page.
What happens if I send an unknown unit?
Unknown or misspelled units are never silently mapped.
How are conversion factors defined?
All conversions bridge through watts per meter-kelvin using fixed definitions: 1 BTU/(h·ft·°F) = 1.7307346664 W/(m·K) (IT Btu, international foot), and 1 cal/(s·cm·°C) = 418.4 W/(m·K) (thermochemical calorie).
Does this compute heat flux or thermal diffusivity?
No. This capability converts thermal conductivity units only. Fourier heat flux, U-values, and thermal diffusivity are out of scope here.
What is 1 cal/(s·cm·°C) in W/(m·K)?
Exactly 418.4 W/(m·K). Older CGS tables and some chemistry references still list pure substances in calories per second centimeter Celsius, so this is the step that brings them into an SI materials table.
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-conductivity \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"value":1,"from":"W_m_K","to":"BTU_h_ft_F"}'const res = await fetch("https://api.kit.forhosting.com/conv/thermal-conductivity", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"value": 1,
"from": "W_m_K",
"to": "BTU_h_ft_F"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/thermal-conductivity",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"value": 1,
"from": "W_m_K",
"to": "BTU_h_ft_F"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/thermal-conductivity", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"value":1,"from":"W_m_K","to":"BTU_h_ft_F"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"value":1,"from":"W_m_K","to":"BTU_h_ft_F"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/thermal-conductivity", 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,
"from": "W_m_K",
"to": "BTU_h_ft_F"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.thermal_conductivity",
"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_value | 1000000000000000000 |
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
Supported units are watts per meter-kelvin, BTU per hour foot Fahrenheit, and calories per second centimeter Celsius, plus everyday aliases such as W/(m·K), W/m·K, BTU/(h·ft·°F), Btu/h·ft·F, and cal/(s·cm·°C).
What the thermal conductivity converter returns and which units it understands
There is no temperature-dependent material model and no Fourier heat-flux path: the engine either multiplies and divides by fixed factors inside the supported magnitude range or rejects the input with invalid_input. Rejected cases include missing value, from, or to; non-finite numbers; magnitudes above the documented ceiling; and any unit string that is not on the supported list.
How factors are defined and how results stay reproducible
Optional scientific notation on the value string is allowed when it parses as a finite decimal; embedded spaces, hex prefixes, and non-numeric tokens are rejected with a clear message so a bad cell does not become a wrong material property. Zero is a valid value and simply yields zero in the target unit. Computation multiplies value by the source factor in watts per meter-kelvin, then divides by the target factor: one BTU per hour foot Fahrenheit equals one point seven three zero seven three four six six six four watts per meter-kelvin using the international foot and the international table British thermal unit; one thermochemical calorie per second centimeter Celsius equals exactly four hundred eighteen point four watts per meter-kelvin. The preferred fields are value for the conductivity magnitude, from for the source unit, and to for the target unit, with aliases amount, conductivity, k, lambda, and quantity for the value, unit, from_unit, source, and input_unit for from, and target, to_unit, output_unit, and into for to so heterogeneous clients can share one contract. An optional precision field, with aliases decimals and dp, chooses how many decimal places to expose for value, result, and value_wmk, defaulting to ten and capped at fifteen so JSON goldens stay stable. Kelvin and Celsius temperature intervals are identical, so W/(m·°C) aliases map to the same SI id. Pair the free browser run on this page with the priced API when you need the identical mathematical result inside an automated pipeline without re-implementing unit tables yourself.
Where thermal conductivity conversion fits in materials, buildings, and software
On this page the work runs entirely in your browser; through the API each successful lookup costs $0.002, failed validation is not charged, and nothing is stored after the response returns. That split — free interactive exploration and a priced, identical API — matches the rest of the KIT tier-A catalog and lets you move from a classroom demo to an automated pipeline without changing the mathematical result.
Integration use cases
Homework and CI fixtures
Generate reproducible thermal conductivity conversions for worksheets, tutoring software, and unit tests that assert fixed SI and engineering factors.
Technical questions
Which thermal conductivity units are supported?
Watts per meter-kelvin (W_m_K), BTU per hour foot Fahrenheit (BTU_h_ft_F), and calories per second centimeter Celsius (cal_s_cm_C), including common aliases such as W/(m·K), BTU/(h·ft·°F), and cal/(s·cm·°C).