degree Rankine (°R)
1 degree Rankine = 0.55555556 kelvins
What is degree Rankine?
Degree Rankine is an absolute temperature scale based on Fahrenheit-sized degrees, where zero is absolute zero. It is used in engineering thermodynamics in the United States, particularly in aerospace and mechanical engineering calculations.
Notes: K = °R * 5/9
Real-world uses
The Rankine scale is used in some American engineering fields, particularly thermodynamics, combustion engineering, and heat transfer calculations where an absolute temperature in Fahrenheit-sized degrees is needed. It appears in US engineering textbooks and ASHRAE standards.
History
Named after Scottish-Irish engineer William John Macquorn Rankine, who proposed it in 1859. It serves as the Fahrenheit-scale analogue of kelvin. While kelvin uses Celsius-sized degrees from absolute zero, Rankine uses Fahrenheit-sized degrees from absolute zero.
Common mistakes
Confusing Rankine with Fahrenheit—Rankine starts at absolute zero (0°R = −459.67°F), not at 0°F. Also, forgetting that the conversion from Fahrenheit is simply °R = °F + 459.67.
When is this conversion used?
Converting between degree Rankine and kelvin is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region.
How to convert degree Rankine to kelvin
Formula: K = °R × 5/9
Conversion formula (from base unit)
(x * 5.0/9.0)
Measurement standards
The kelvin is the SI base unit of thermodynamic temperature, defined by fixing the Boltzmann constant to exactly 1.380649 × 10⁻²³ joules per kelvin. This definition, adopted in 2019, decoupled the kelvin from the triple point of water.
Did you know?
The coldest temperature ever recorded on Earth was −89.2 °C (−128.6 °F) at the Soviet Vostok Station in Antarctica on 21 July 1983. In laboratories, scientists have cooled atoms to within billionths of a kelvin above absolute zero.
| degrees Rankine | kelvins |
|---|---|
| 0 | 0 |
| 10 | 5.55555556 |
| 20 | 11.11111111 |
| 25 | 13.88888889 |
| 37 | 20.55555556 |
| 50 | 27.77777778 |
| 100 | 55.55555556 |
| 200 | 111.11111111 |
| 500 | 277.77777778 |
Common values
| degrees Rankine | kelvins | |
|---|---|---|
| Water freezes | 491.67 degrees Rankine | 273.15 kelvins |
| Room temperature | 529.47 degrees Rankine | 294.15 kelvins |
| Human body | 558.27 degrees Rankine | 310.15 kelvins |
| Oven baking | 815.67 degrees Rankine | 453.15 kelvins |
| Water boils | 671.67 degrees Rankine | 373.15 kelvins |
Full degree Rankine conversion table
| Unit | Value | Factor |
|---|---|---|
| degree Celsius | 1 °R = -272.59444444 °C | °C = °R × 0.555556 − 273.15 |
| degree Fahrenheit | 1 °R = -458.67 °F | °F = °R − 459.67 |
| kelvin | 1 °R = 0.55555556 K | K = °R × 5/9 |
| degree Réaumur | 1 °R = -218.07555556 °Re | °Re = °R × 0.444444 − 218.52 |