Specific Heat Converter

Specific heat capacity is the amount of heat energy needed to raise the temperature of one unit mass of a substance by one degree. Its SI unit is the joule per kilogram per kelvin, J/(kg·K). Water has a high specific heat of about 4,186 J/(kg·K), which is why it stores and releases heat slowly and moderates climate. A temperature interval of one kelvin equals one degree Celsius, so J/(kg·K) and J/(kg·°C) are numerically identical.

The calorie used in this converter is the thermochemical calorie, defined as exactly 4.184 joules. Because one calorie per gram per degree Celsius equals 4.184 J per 0.001 kg per kelvin, 1 cal/(g·°C) = 4,184 J/(kg·K). This is why the specific heat of water is approximately 1 cal/(g·°C) and approximately 4,184 J/(kg·K) at the same time.

BTU/(lb·°F) is the customary US engineering unit of specific heat. By the way the British thermal unit and the Fahrenheit degree are defined, 1 BTU/(lb·°F) equals exactly 1 cal/(g·°C) numerically, which is 4,184 J/(kg·K). So water's specific heat is approximately 1 BTU/(lb·°F) as well. This neat coincidence makes the three everyday water values (1 cal/g/°C, 1 BTU/lb/°F, 4,184 J/kg/K) easy to remember.

Yes, for most substances specific heat varies with temperature, though often only modestly over everyday ranges. Tabulated values are usually quoted at a specified reference temperature, commonly 25°C, or as an average over a range. For precise engineering work, use a value measured at your working temperature. This converter changes units only; it does not adjust for temperature dependence.