Rankine to Celsius conversion
Rankine is an absolute temperature scale based on the Fahrenheit scale whereas Celsius is a relative temperature scale. The Rankine scale is normally only used in the United States while the Celsius scale is used worldwide.
There are two steps to converting Rankine to Celsius; first subtract 491.67 and then divide the result by 1.8.
The reason that 491.67 is subtracted at the beginning is a combination of two steps. By subtracting 459.67, Rankine is converted to Fahrenheit. To convert Fahrenheit to Celsius you first need to subtract 32 before applying the factor of 1.8. Since the two subtractions are consecutive they can be combined: -491.67 -32 = -491.67.
For example, suppose you are converting 600 Rankine. First subtract 491.67 which makes 108.33, now divide by 1.8 making 60.18°C.
Definition of Rankine and Celsius
Rankine is an absolute temperature scale used mainly in the United States. It is named after the Scottish engineer and physicist William John Macquorn Rankine. The Rankine scale is based on the Fahrenheit scale but starts at absolute zero making 0 Rankine = -459.67°F.
Celsius (sometimes referred to as Centigrade) is the most widely used temperature scale. The freezing point of water is 0 degrees C and the boiling point 100 degrees C.
Why is Rankine used?
Rankine is almost exclusively used in the United States. As is the Kelvin scale, Rankine is an absolute scale but it is based on Fahrenheit rather than Celsius.
Where Fahrenheit is predominately used, Rankine provides an absolute scale equivalent for certain applications in science.
Rankine is used in thermodynamics because, as an absolute scale, it allows for conversion between temperature and energy.
The use of Rankine is limited to very specific industries and the Kelvin scale is increasingly replacing it over time.
