Kelvin to Rankine (K to °R)
1 kelvin equals 1.8 degrees Rankine exactly.
How to convert kelvins to degrees Rankine
To convert kelvins to degrees Rankine, multiply the number of kelvins by 1.8. This factor is exact. To go the other way, multiply degrees Rankine by 0.5555555556 (rounded).
degrees Rankine = kelvins × 1.8
Example: 10 kelvins = 18 degrees Rankine.
Temperature scales have different zero points, so converting is not just multiplication. Differences in degrees convert differently from absolute readings.
About these units
Kelvin (K)
The SI base unit of temperature. Zero kelvin is absolute zero, where particles have minimal thermal motion. A kelvin step is the same size as a Celsius degree.
Lord Kelvin, born William Thomson, published an absolute temperature scale in 1848 and refined it with James Joule in 1854. Its zero sits at absolute zero, and its degree is the same size as a Celsius degree. The kelvin entered the SI in 1954, defined as 1/273.16 of the thermodynamic temperature of the triple point of water, where ice, liquid and vapor coexist. In 1967 the 13th CGPM renamed the unit from the degree Kelvin to simply the kelvin, with symbol K, and no word degree.
Since 20 May 2019 the kelvin has been defined by fixing the Boltzmann constant at exactly 1.380649 times 10 to the minus 23 joule per kelvin, which frees it from the properties of any one substance. Scientists use it for stars and cryogenics, and lighting designers use it for color temperature. NIST notes that incandescent bulbs run near 3,000 K, daylight lamps at 5,000 to 5,600 K, and the Sun's surface at about 5,800 K. Room temperature, about 21 degrees Celsius, is roughly 294 K.
The kelvin is the reference unit for temperature on this site.
Sources: NIST: the kelvin and the SI redefinition; BIPM: 13th CGPM (1967), Resolution 3; Wikipedia: Kelvin
Degree Rankine (°R)
An absolute scale with Fahrenheit-sized degrees: 0 °R is absolute zero. Used in some engineering thermodynamics.
Scottish engineer and physicist William John Macquorn Rankine of the University of Glasgow proposed this scale in 1859. His idea was simple: keep the size of the Fahrenheit degree but start counting at absolute zero, so that no temperature is ever negative. Zero on the scale is therefore 0 K, which equals about minus 459.67 degrees Fahrenheit, and a reading in Rankine is just the Fahrenheit reading plus 459.67.
Because one Rankine degree is exactly 5/9 of a kelvin, converting is a matter of multiplying by 5/9 or, going the other way, multiplying kelvins by 9/5. NIST states the same relation as kelvin equal to the Rankine value divided by 1.8. Water freezes at 491.67 degrees Rankine and boils at roughly 671.64 degrees on the same scale. The scale appears mainly in some thermodynamics and heat-transfer calculations in US engineering, where data are tabulated in Fahrenheit-sized degrees. Everywhere else, kelvins and Celsius degrees have taken over, and the symbol is sometimes written °Ra to avoid confusion with the Rømer and Réaumur scales.
1 degree Rankine = 0.5555555556 kelvins (approximately).
Sources: Wikipedia: Rankine scale; NIST SP 811, Appendix B.8 conversion factors
Related conversions
- Rankine to kelvin (reverse)
- Kelvin to Celsius
- Kelvin to Fahrenheit
- Kelvin to Réaumur
- Kelvin to Delisle
- Kelvin to Newton
- Kelvin to Rømer
- Celsius to Rankine
- Fahrenheit to Rankine
See all temperature units.