How to convert Rankine to Kelvin
K = °R × 5/9
Apply the operations in the order shown. This formula converts a Rankine temperature reading to Kelvin, not a temperature difference. The source reading must be at least 0 °R, the absolute-zero limit.
Worked examples
491.67 °R ≈ 273.15 K
491.67 × 5/9 ≈ 273.15
Water’s familiar freezing reference near standard atmospheric pressure.
671.67 °R ≈ 373.15 K
671.67 × 5/9 ≈ 373.15
Water’s familiar boiling reference near standard atmospheric pressure; actual boiling temperature changes with pressure.
Frequently asked questions
Can I use °R to K for a temperature difference?
For an interval, use only the degree-size ratio and omit any offset. This calculator converts scale readings. Kelvin and Rankine start at absolute zero; Celsius and Fahrenheit have different zero points.