1/°R

per Rankine degree

Thermal expansion coefficientexact by definition

The per Rankine degree is exactly 9/5 per kelvin, the same size as per Fahrenheit degree. It is used where the surrounding calculation carries absolute temperature, as in the ideal-gas expansion coefficient 1/T, which is 1/519.67 °R⁻¹ at 60 °F.

1 1/°R 1.8 1/K