Rankine to Celsius Converter
Formula
°C = (°R − 491.67) × 5/9
To convert Rankine to Celsius, subtract 491.67 then multiply by 5/9.
How to use
- Type your temperature into the Rankine field.
- The tool subtracts 491.67, then multiplies by 5/9.
- Read the converted temperature in Celsius below.
Example
Enter 671.67 Rankine: (671.67 − 491.67) × 5/9 = 180 × 5/9 = 100°C, the boiling point of water.
Frequently Asked Questions
What is 491.67°R in Celsius?
491.67°R = 0°C (freezing point of water).
What is absolute zero in Rankine and Celsius?
Absolute zero is 0°R on the Rankine scale, which equals -273.15°C. Both Rankine and Kelvin start at this point, the theoretical temperature where molecular motion stops. The difference is that Rankine uses Fahrenheit-sized degrees while Kelvin uses Celsius-sized degrees.
When would I actually use the Rankine scale?
Rankine is mostly used in US engineering and thermodynamics, especially in fields like aerospace, HVAC, and power generation where Fahrenheit is the working unit but an absolute scale is needed for gas-law and heat-engine calculations. Outside of those technical contexts it is rarely seen, so most conversions to Celsius are done for academic or cross-discipline reference. To convert, subtract 491.67 from the Rankine value, then multiply by 5/9.