Heat capacity unit conversion refers to the process of converting heat capacity values from one unit to another. 

Heat capacity, also known as thermal capacity, is a measure of the amount of heat energy required to raise the temperature of a substance by one degree Celsius or Kelvin.

Heat capacity is typically measured in units such as joules per degree Celsius (J/°C), joules per Kelvin (J/K), calories per degree Celsius (cal/°C), or calories per Kelvin (cal/K). Converting between these units may be necessary for various applications in science, engineering, and everyday life.

To perform heat capacity unit conversion, specific conversion factors are used depending on the units involved. 

For example:

• To convert heat capacity from joules per degree Celsius to joules per Kelvin, no conversion is needed because the size of a degree Celsius and a Kelvin is the same.
• To convert from calories per degree Celsius to joules per degree Celsius, you would use the conversion factor: 1 calorie = 4.184 joules.
•  To convert from calories per Kelvin to joules per Kelvin, the same conversion factor (1 calorie = 4.184 joules) would apply.

By converting heat capacity units, we can express heat capacity values in the most appropriate units for a given context, making it easier to perform calculations, analyze data, and communicate information effectively.