Convert Celsius to Rankine
Convert degrees celsius to degrees rankine instantly. °R = (°C × 9/5) + 491.67 — use the live calculator, the exact formula, a reference-temperature table and worked examples. Also check the Rankine to Celsius converter for the reverse conversion.
Units explained
Celsius
The degree Celsius (°C) is the SI's everyday temperature unit. One degree Celsius is exactly the same size as one kelvin, with the zero point shifted so that 0 °C = 273.15 K. Water freezes near 0 °C and boils near 100 °C at standard atmospheric pressure.
Named for Swedish astronomer Anders Celsius, who in 1742 proposed a 100-degree scale between the boiling and freezing points of water. His original scale ran in reverse (0 at boiling, 100 at freezing); it was inverted to the modern direction shortly after his death.
The world's standard everyday temperature scale, used in nearly every country — including throughout India — for weather forecasts, cooking, medicine, science classrooms, and industry.
Devised by Anders Celsius at Uppsala University, Sweden, in 1742; the inverted modern form was in use by 1745, and the name 'degree Celsius' replaced 'degree centigrade' internationally at the 9th CGPM in 1948.
Rankine
The degree Rankine (°R) is the absolute counterpart of the Fahrenheit scale: 0 °R is absolute zero, and one degree Rankine is exactly the same size as one degree Fahrenheit (5/9 of a kelvin). Water freezes at 491.67 °R.
Named for William John Macquorn Rankine, the Scottish engineer and physicist who proposed an absolute scale built from Fahrenheit-sized degrees, paralleling Kelvin's absolute scale built from Celsius-sized degrees.
Used mainly in United States aerospace, thermodynamics, and power-plant engineering, where calculations demand absolute temperature but legacy data, instruments, and codes are in Fahrenheit.
Proposed by W. J. M. Rankine at the University of Glasgow in 1859, eleven years after Lord Kelvin's absolute scale of 1848.
Celsius to Rankine conversion formula
The exact relationship between degrees celsius and degrees rankine:
To convert degrees celsius to degrees rankine, multiply the value by 9/5, then add 491.67. To reverse, multiply the value by 5/9, then subtract 273.15.
Reference anchors: water freezes at 0 °C = 491.67 °R and boils at 100 °C = 671.67 °R (at standard atmospheric pressure).
How to use this converter
Type a value into the calculator. The result in degrees rankine updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Rankine to Celsius converter for the reverse direction.
Step-by-step: convert degrees celsius to degrees rankine
- Write down the temperature in degrees celsius (°C).
- Multiply the value by 9/5, then add 491.67.
- The result is the same temperature expressed in degrees rankine (°R).
- To reverse, multiply the value by 5/9, then subtract 273.15 — or open the Rankine to Celsius converter.
Worked examples
Example 1 — Convert 37 °C to °R (human body temperature):
(37 × 9/5) + 491.67 = 558.27 °R
Example 2 — Convert 100 °C to °R (the boiling point of water):
(100 × 9/5) + 491.67 = 671.67 °R
Celsius to Rankine conversion table
Physically meaningful reference temperatures, from absolute zero to the surface of the Sun, converted from degrees celsius to degrees rankine:
| Celsius [°C] | Rankine [°R] | Reference point |
|---|---|---|
| -273.15 | 0 | Absolute zero |
| -40 | 419.67 | Where Celsius and Fahrenheit coincide (−40°) |
| -17.7777777778 | 459.67 | Zero Fahrenheit (0 °F) |
| 0 | 491.67 | Water freezes (0 °C / 32 °F) |
| 0.01 | 491.688 | Triple point of water |
| 10 | 509.67 | Cool day (10 °C / 50 °F) |
| 20 | 527.67 | Room temperature (20 °C / 68 °F) |
| 25 | 536.67 | Standard laboratory temperature (25 °C) |
| 30 | 545.67 | Hot day (30 °C / 86 °F) |
| 37 | 558.27 | Human body temperature (37 °C / 98.6 °F) |
| 40 | 563.67 | Heat-wave day (40 °C / 104 °F) |
| 50 | 581.67 | Hot tap water (50 °C / 122 °F) |
| 100 | 671.67 | Water boils (100 °C / 212 °F) |
| 180 | 815.67 | Moderate baking oven (180 °C / 356 °F) |
| 5504.85 | 10400.4 | Surface of the Sun (≈5,505 °C) |
Frequently asked questions
What is 37 °C in °R?
How do I convert degrees celsius to degrees rankine?
How do I convert degrees rankine back to degrees celsius?
At what temperature do the Celsius and Rankine scales read the same number?
Can a temperature be below absolute zero?
Popular temperature unit conversions
Convert Celsius to other temperature units
Show all Celsius conversions
Modern Standard Scales (3 units)
Historical Scales (4 units)
Scientific & Fixed-Point (3 units)
Sources & references
Conversion relationship (°R = (°C × 9/5) + 491.67) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- BIPM — International Temperature Scale of 1990 (ITS-90)
The internationally agreed practical temperature scale, defining fixed points (including the triple point of water at 273.16 K) and interpolation instruments used by national metrology institutes for thermometer calibration worldwide.
- CODATA Internationally Recommended Values of the Fundamental Physical Constants
Committee on Data of the International Science Council; authoritative source for the masses of fundamental particles (electron, proton, neutron) and the atomic mass constant.