Skip to main content

Celsius to Rankine Converter
↔ Convert °R to °C instead

Common Conversions

°C °R
-273.15 0
-200 131.67
-100 311.67
-40 419.67
0 491.67
20 527.67
25 536.67
37 558.27
100 671.67
200 851.67
500 1391.67
1000 2291.67

Why this conversion matters in chemistry

Rankine is what Kelvin would be if it used Fahrenheit-sized degrees: an absolute temperature scale starting at 0 °R = −459.67 °F with the same degree size as Fahrenheit. Chemistry does almost everything in Kelvin, but steam tables and hydrocarbon property data in old US engineering references still report in Rankine, and equations of state like Peng-Robinson and SRK get written in whichever system the textbook did. Adding 273.15 and multiplying by 9/5 is the composite step — first to Kelvin, then out to the English absolute scale — that lets a reaction studied at 25 °C (298.15 K, 536.67 °R) land in the right column of a thermodynamic property table.

Formula

°R = (°C + 273.15) × 9/5

Worked Examples

0°C = 491.67°R

The freezing point of water — a fixed calibration point in both absolute and Celsius scales.

100°C = 671.67°R

Water's normal boiling point at 1 atm.

25°C = 536.67°R

The standard reference temperature behind tabulated Gibbs free energies and most thermochemical data.

-273.15°C = 0°R

Absolute zero — the shared origin of both Rankine and Kelvin.

Frequently Asked Questions

How do I convert Celsius to Rankine?
Add 273.15 to the Celsius value to get Kelvin, then multiply by 9/5. So 25 °C becomes 298.15 K, and 298.15 × 9/5 gives 536.67 °R.
Is the Celsius-to-Rankine step the same as Fahrenheit-to-Celsius?
No. Rankine is an absolute scale with zero at absolute zero; Fahrenheit has an arbitrary zero. The degree size is the same as Fahrenheit's, but the offset between the two scales is 459.67.
When does a chemist actually need Rankine?
Mostly when working from US-tradition engineering references — steam tables, combustion calculations, hydrocarbon-process property data, or older editions of Perry's Chemical Engineers' Handbook that report in English absolute units.
What is room temperature in Rankine?
About 536.67 °R at 25 °C, which is also 298.15 K and 77 °F. Useful to keep in mind when a calculation has to span three temperature conventions at once.