Specific heat capacity converter
4184 J/(kg·K) is exactly 1 cal/(g·°C). Convert a specific heat capacity between joules per kilogram-kelvin, calories per gram-degree Celsius and BTU per pound-degree Fahrenheit when datasheets, textbooks and lab results use different units. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Value
- 4,184
- Source unit: J/
- J/(kg·K)
- Target unit: J/
- cal/(g·°C)
- Result
- 1
- Converted
- 1
- Value j per kg k
- 4,184
- Factor
- 0.0002390057
A specific heat capacity converter turns one material property reading into another unit without spreadsheet formulas or mental factor tables. Enter a finite value plus a source unit and a target unit among joules per kilogram-kelvin, thermochemical calories per gram-celsius, and British thermal units per pound-fahrenheit; the tool returns the converted capacity, the SI intermediate in J/(kg·K), the exact unit factor applied, and step-by-step substitution lines you can paste into a report. Thermal engineers comparing datasheets, students converting textbook tables between SI and customary units, process chemists checking calorimeter results, and HVAC techs reading mixed property charts all need the same deterministic path.
Which specific heat units are supported and how conversion works
This capability converts among three everyday specific heat capacity units that dominate materials tables, chemistry labs, thermodynamics homework, and engineering datasheets. Joules per kilogram-kelvin (J/(kg·K)) are the SI coherent unit and the internal hub: every conversion multiplies the input by how many joules per kilogram-kelvin equal one source unit, then divides by how many joules per kilogram-kelvin equal one target unit. Because a kelvin interval equals a celsius interval, J/(kg·°C) is treated as identical to J/(kg·K) for conversion purposes.
Thermochemical calories per gram-celsius use the exact factor four thousand one hundred eighty-four, from one thermochemical calorie of four point one eight four joules per gram scaled by one thousand grams per kilogram. British thermal units per pound-fahrenheit use the International Table BTU of one thousand fifty-five point zero five five eight five two six two joules, the international pound of zero point four five three five nine two three seven kilograms, and the Fahrenheit interval of five ninths of a kelvin.
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 unit analysis, pair classic examples such as four thousand one hundred eighty-four joules per kilogram-kelvin equaling one calorie per gram-celsius for liquid water near room temperature tables, and one BTU per pound-fahrenheit converting to about four thousand one hundred eighty-six point eight joules per kilogram-kelvin. Stay inside the absolute range so intermediate SI values cannot overflow.
This landing targets people searching for a specific heat capacity converter, J/kgK to cal/gC, BTU/lbF to SI, or calorie per gram celsius online; it is not a general length-weight-temperature unit converter, not a mixing-temperature calculator, and not a thermal conductivity tool.
What you can do with it
Materials datasheet unit alignment
Engineers convert supplier specific-heat tables from cal/(g·°C) or BTU/(lb·°F) into SI J/(kg·K) for consistent CAD thermal models and finite-element material cards.
Lab and calorimetry reporting
Chemists and physics labs convert measured heat capacities between calorie-based lab books and SI lab information systems without hand factor mistakes.
HVAC and process energy checks
Technicians convert fluid property charts between customary BTU/(lb·°F) and SI for energy balances, coil sizing notes, and cross-standard design reviews.
FAQ
How is one calorie per gram-celsius defined here?
One cal/(g·°C) equals exactly 4184 J/(kg·K), using the thermochemical calorie of 4.184 J and scaling grams to kilograms.
Is the specific heat capacity converter free?
The browser tool is free and runs locally.
How many J/(kg·K) is 1 BTU/(lb·°F)?
About 4186.8 joules per kilogram-kelvin. The factor combines the International Table BTU, the international pound of 0.45359237 kilograms and the Fahrenheit degree, which is five ninths of a kelvin.
Is J/(kg·°C) the same as J/(kg·K)?
Yes, for specific heat. A change of one kelvin is the same size as a change of one degree Celsius, so a value per kelvin and a value per degree Celsius are numerically identical.
Do I get my original value back after a round trip?
Yes. Every conversion passes through joules per kilogram-kelvin, so converting from one unit to another and back recovers the original within the published twelve-decimal rounding.
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/specific-heat \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"value":4184,"from":"J/(kg·K)","to":"cal/(g·°C)"}'const res = await fetch("https://api.kit.forhosting.com/conv/specific-heat", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"value": 4184,
"from": "J/(kg·K)",
"to": "cal/(g·°C)"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/specific-heat",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"value": 4184,
"from": "J/(kg·K)",
"to": "cal/(g·°C)"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/specific-heat", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"value":4184,"from":"J/(kg·K)","to":"cal/(g·°C)"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"value":4184,"from":"J/(kg·K)","to":"cal/(g·°C)"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/specific-heat", 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": 4184,
"from": "J/(kg·K)",
"to": "cal/(g·°C)"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.specific_heat",
"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 specific heat units are supported and how conversion works
Common aliases are accepted case-insensitively: J/kg/K, J/kg-K, and joules per kilogram kelvin for J/(kg·K); cal/g/C, cal/g-C, and calories per gram celsius for cal/(g·°C); and BTU/lb/F, BTU/lb-F, and btu per pound fahrenheit for BTU/(lb·°F). 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. 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 specific heat reading and only need a second unit for display, datasheet comparison, or regulatory reporting without shipping floating conversion tables in every app binary. Send a JSON body with three required fields: value (aliases c, cp, amount, and n), 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_j_per_kg_k as the SI intermediate, 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 three 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 J/(kg·K), cal/(g·°C), and BTU/(lb·°F) so automated tests stay stable. Prefer this capability when both endpoints are among the three supported specific-heat units and you need deterministic factors and step strings; if you only need equilibrium temperature after mixing masses, use a dedicated thermo mixing capability 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 specific heat units can I convert?
Joules per kilogram-kelvin (J/(kg·K)), thermochemical calories per gram-celsius (cal/(g·°C)), and British thermal units per pound-fahrenheit (BTU/(lb·°F)), including common aliases such as J/kg/K, cal/g/C, and BTU/lb/F.
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.
Are results deterministic across browser and API?
Yes. Handler and widget share the same lib.js solve path with fixed conversion factors and twelve-decimal rounding, so golden examples match production.