Convert Joules per Kilogram per Kelvin to Btu (IT) per Pound per °F
Joule per Kilogram per Kelvin (J/(kg·K)) to Btu (IT) per Pound per °F (Btu/(lb·°F)) specific heat capacity conversion — enter any value below to get an instant result, or use the table for common values.
Results from this calculator are estimates provided for general informational purposes only, based on formulas, rates, and standards commonly accepted as of 2026. Figures may differ slightly from other calculators or professional sources due to rounding methods, differing assumptions, or regional regulations, and rules may change over time. Always consult a qualified professional — such as a financial advisor, healthcare provider, or other relevant specialist — before making decisions based on these results.
Result
1 J/(kg·K) = 0.0002388459 Btu/(lb·°F)
1 Joule per Kilogram per Kelvin = 0.0002388459 Btu (IT) per Pound per °F
1 Btu (IT) per Pound per °F = 4186.8 Joules per Kilogram per Kelvin
1 J/(kg·K) in every supported unit
Conversion chart: Joule per Kilogram per Kelvin to Btu (IT) per Pound per °F
Conversion table
| Joule per Kilogram per Kelvin (J/(kg·K)) | Btu (IT) per Pound per °F (Btu/(lb·°F)) |
|---|---|
| 0.01 J/(kg·K) | 2.38846E-06 Btu/(lb·°F) |
| 0.1 J/(kg·K) | 2.38846E-05 Btu/(lb·°F) |
| 1 J/(kg·K) | 0.0002388459 Btu/(lb·°F) |
| 2 J/(kg·K) | 0.00047769179 Btu/(lb·°F) |
| 3 J/(kg·K) | 0.00071653769 Btu/(lb·°F) |
| 5 J/(kg·K) | 0.0011942295 Btu/(lb·°F) |
| 10 J/(kg·K) | 0.002388459 Btu/(lb·°F) |
| 20 J/(kg·K) | 0.0047769179 Btu/(lb·°F) |
| 50 J/(kg·K) | 0.011942295 Btu/(lb·°F) |
| 100 J/(kg·K) | 0.02388459 Btu/(lb·°F) |
| 1000 J/(kg·K) | 0.2388459 Btu/(lb·°F) |
Joule per Kilogram per Kelvin (J/(kg·K))
Definition: The SI derived unit of specific heat capacity — the joules of energy needed to raise the temperature of one kilogram of a substance by one kelvin.
History: Formed directly from the joule, kilogram, and kelvin once all three were standardized as SI units, giving thermodynamics a single coherent unit consistent with all other SI energy and mass calculations.
Current use: The standard unit in physics, chemistry, and engineering thermodynamics worldwide for comparing how much energy different materials store per degree of heating.
Btu (IT) per Pound per °F (Btu/(lb·°F))
Definition: The US customary specific heat capacity unit — Btu of energy needed to raise one pound of a substance by one degree Fahrenheit, and, by the same historical construction as the calorie, almost exactly 1 for water.
History: Defined analogously to the calorie but using US customary pound and Fahrenheit degree, giving American engineers a heat-capacity unit consistent with everyday US mass and temperature measurements.
Current use: The standard specific heat unit on US engineering datasheets, HVAC load calculations, and industrial process heat-transfer worksheets.
Supported Units
| Unit | Symbol | In J/(kg·K) |
|---|---|---|
| Joule per Kilogram per Kelvin | J/(kg·K) | 1 J/(kg·K) |
| Kilojoule per Kilogram per Kelvin | kJ/(kg·K) | 1000 J/(kg·K) |
| Joule per Gram per °C | J/(g·°C) | 1000 J/(kg·K) |
| Calorie (IT) per Gram per °C | cal/(g·°C) | 4186.8 J/(kg·K) |
| Kilocalorie (IT) per Kilogram per °C | kcal/(kg·°C) | 4186.8 J/(kg·K) |
| Btu (IT) per Pound per °F | Btu/(lb·°F) | 4186.8 J/(kg·K) |
| Btu (IT) per Pound per °C | Btu/(lb·°C) | 2326 J/(kg·K) |
| Kilogram-force Meter per Kilogram per Kelvin | kgf·m/(kg·K) | 9.80665 J/(kg·K) |
| Pound-force Foot per Pound per °R | lbf·ft/(lb·°R) | 5.3803205 J/(kg·K) |
About These Parameters
- Value
- The specific heat capacity value you want to convert, expressed in the "From" unit. Accepts decimals.
- From Unit
- The unit your input value is currently measured in — a chemistry reference's cal/(g·°C), or a US engineering datasheet's Btu/(lb·°F).
- To Unit
- The unit you want the result converted into. Use the swap button to flip From and To instantly.
How Specific Heat Capacity Conversion Works
The Formula
Every unit here is defined by a fixed multiplier relative to joules per kilogram per kelvin. To convert a value from one unit to another:
result = value × (factor of "From" unit ÷ factor of "To" unit)
For Joule per Kilogram per Kelvin → Btu (IT) per Pound per °F: multiply by 0.0002388459. For example, 1 J/(kg·K) × 0.0002388459 = 0.0002388459 Btu/(lb·°F).
Q = mcΔT
Specific heat capacity (c) is the key figure in the fundamental heat-energy equation Q = mcΔT — the heat energy Q needed equals mass (m) times specific heat capacity (c) times the temperature change (ΔT). This is the formula behind everything from calculating how much energy it takes to boil a kettle of water to sizing an industrial heat exchanger.
Why Water Is the Reference Point
Water has an unusually high specific heat capacity (about 4,186 J/(kg·K), or almost exactly 1 cal/(g·°C) by the calorie's original definition) compared to most other everyday materials — metals typically sit between 100 and 900 J/(kg·K). This is why large bodies of water moderate coastal climates, why water is used as a coolant in engines and power plants, and why the calorie and Btu, both originally water-based reference units, come out so close to a value of 1 on this page's water-referenced units.
Example
A specific heat capacity of 1 J/(kg·K) equals 0.0002388459 Btu/(lb·°F). For scale, water's specific heat capacity is about 4,186 J/(kg·K) (1 cal/(g·°C)), while aluminum's is about 897 J/(kg·K) — meaning it takes roughly 4.7 times more energy to heat a kilogram of water by one degree than the same mass of aluminum.
Frequently Asked Questions
How many Btu (IT) per Pound per °F are in 1 Joule per Kilogram per Kelvin?
1 Joule per Kilogram per Kelvin (J/(kg·K)) equals exactly 0.0002388459 Btu (IT) per Pound per °F (Btu/(lb·°F)).
Why is water's specific heat capacity almost exactly 1 cal/(g·°C)?
It's not a coincidence — the calorie was originally DEFINED in the 19th century as the energy needed to raise one gram of water by one degree Celsius. The modern International Table calorie is now fixed to a precise joule value rather than redefined by experiment each time, which is why the figure comes out extremely close to, but not perfectly, 1.
What's the difference between specific heat capacity and heat capacity?
Specific heat capacity is a per-unit-mass property of a substance (energy per kg per degree), independent of how much of the substance you have. Heat capacity (without "specific") is the total energy needed to heat a particular object or quantity by one degree, found by multiplying specific heat capacity by the actual mass involved.
How accurate are these conversions?
Every conversion factor used here is the exact, internationally recognized relationship between the underlying energy, mass, and temperature units (e.g. 1 cal (IT) = exactly 4.1868 joules) — results are limited only by floating-point display precision, not by rounded conversion constants.