Convert Rankine to Fahrenheit
Convert degrees rankine to degrees fahrenheit instantly. °F = °R − 459.67 — use the live calculator, the exact formula, a reference-temperature table and worked examples. Also check the Fahrenheit to Rankine converter for the reverse conversion.
Units explained
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.
Fahrenheit
The degree Fahrenheit (°F) sets the freezing point of water at 32 °F and the boiling point at 212 °F, dividing the interval into 180 equal degrees. One degree Fahrenheit is exactly 5/9 the size of a kelvin, and °F = °C × 9/5 + 32 exactly.
Created by German-born physicist Daniel Gabriel Fahrenheit, inventor of the reliable mercury-in-glass thermometer. His zero point was the temperature of an ice-and-salt brine mixture, and his original upper fixed point sat near human body temperature.
The official everyday scale of the United States and a handful of other countries. In India, clinical thermometers and fever readings are still very commonly quoted in Fahrenheit (a '102-degree fever'), which keeps °F to °C conversion a daily need.
Introduced by Daniel Gabriel Fahrenheit in 1724 in Amsterdam, building directly on Ole Rømer's earlier scale, which Fahrenheit had studied during a 1708 visit to Copenhagen.
Rankine to Fahrenheit conversion formula
The exact relationship between degrees rankine and degrees fahrenheit:
To convert degrees rankine to degrees fahrenheit, subtract 459.67 from the value. To reverse, add 459.67 to the value.
Reference anchors: water freezes at 491.67 °R = 32 °F and boils at 671.67 °R = 212 °F (at standard atmospheric pressure).
How to use this converter
Type a value into the calculator. The result in degrees fahrenheit updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Fahrenheit to Rankine converter for the reverse direction.
Step-by-step: convert degrees rankine to degrees fahrenheit
- Write down the temperature in degrees rankine (°R).
- Subtract 459.67 from the value.
- The result is the same temperature expressed in degrees fahrenheit (°F).
- To reverse, add 459.67 to the value — or open the Fahrenheit to Rankine converter.
Worked examples
Example 1 — Convert 1 °R to °F:
1 − 459.67 = -458.67 °F
Example 2 — Convert 100 °R to °F:
100 − 459.67 = -359.67 °F
Rankine to Fahrenheit conversion table
Physically meaningful reference temperatures, from absolute zero to the surface of the Sun, converted from degrees rankine to degrees fahrenheit:
| Rankine [°R] | Fahrenheit [°F] | Reference point |
|---|---|---|
| 0 | -459.67 | Absolute zero |
| 419.67 | -40 | Where Celsius and Fahrenheit coincide (−40°) |
| 459.67 | 0 | Zero Fahrenheit (0 °F) |
| 491.67 | 32 | Water freezes (0 °C / 32 °F) |
| 491.688 | 32.018 | Triple point of water |
| 509.67 | 50 | Cool day (10 °C / 50 °F) |
| 527.67 | 68 | Room temperature (20 °C / 68 °F) |
| 536.67 | 77 | Standard laboratory temperature (25 °C) |
| 545.67 | 86 | Hot day (30 °C / 86 °F) |
| 558.27 | 98.6 | Human body temperature (37 °C / 98.6 °F) |
| 563.67 | 104 | Heat-wave day (40 °C / 104 °F) |
| 581.67 | 122 | Hot tap water (50 °C / 122 °F) |
| 671.67 | 212 | Water boils (100 °C / 212 °F) |
| 815.67 | 356 | Moderate baking oven (180 °C / 356 °F) |
| 10400.4 | 9940.73 | Surface of the Sun (≈5,505 °C) |
Frequently asked questions
What is 1 °R in °F?
How do I convert degrees rankine to degrees fahrenheit?
How do I convert degrees fahrenheit back to degrees rankine?
Do the Rankine and Fahrenheit scales ever read the same number?
Can a temperature be below absolute zero?
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Sources & references
Conversion relationship (°F = °R − 459.67) 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.