Rankine is an absolute Fahrenheit-based temperature scale.
Rankines to Kelvins Converter — R to K
Convert Rankine (R) to Kelvin (K) using the exact temperature formula. See the formula, worked examples, conversion table, history, and common uses.
Rankines to Kelvins converter
Converter
Temperature Converter
Convert Celsius, Fahrenheit, Kelvin, Rankine, Delisle, Newton, Reaumur, and Romer.
Context values
Some unit families need one extra value for a physically accurate result.
Kelvin is the SI absolute temperature scale.
Convert the source temperature to Kelvin, then convert Kelvin to the target scale.
Temperature conversion uses Kelvin as the intermediate absolute scale.
Reserved above the conversion cards and below the converter.
About Converting Rankines to Kelvins
Kelvin is a widely used everyday temperature scale, while Rankine is a historical temperature scale no longer in common use — this conversion is mainly useful for historical reference or comparing older scientific texts against modern figures.
Formula
Convert the source temperature to Kelvin, then convert Kelvin to the target scale.
Both scales are converted through Kelvin as a common absolute reference point.
Simple example
(0 − 32) × 5/9 = 0 °C
0 rankines = 0 kelvins.
Real-world example
(0 − 32) × 5/9 = 0 °C
0 rankines = 0 kelvins.
Conversion table
| Rankine (R) | Kelvin (K) |
|---|---|
| -40 R | -22.22222222 K |
| -20 R | -11.11111111 K |
| 0 R | 0 K |
| 20 R | 11.11111111 K |
| 37 R | 20.55555556 K |
| 100 R | 55.55555556 K |
Reverse conversion: Kelvin to Rankine
(0.5555555556 − 32) × 5/9 = 1 °C
0.5555555556 kelvins = 1 rankines.
Convert the source temperature to Kelvin, then convert Kelvin to the target scale.
For a page dedicated to this direction, see Kelvin to Rankine.
Understanding the Rankine (R)
Rankine is an absolute Fahrenheit-based temperature scale.
Understanding the Kelvin
Kelvin (K) measures temperature. The kelvin is the SI base unit of thermodynamic temperature; 0 K (absolute zero) is the theoretical absence of thermal energy. It is classified as a SI base unit.
Where it's used: Standard scientific temperature unit worldwide
Uses of the Kelvin today
- Scientific and engineering temperature measurement (physics, chemistry)
- Color temperature specifications (lighting, displays)
- Cryogenics and low-temperature physics
History of the Kelvin
The kelvin scale was proposed by William Thomson (Lord Kelvin) in 1848, building on Sadi Carnot's thermodynamic work to define an absolute temperature scale independent of any particular substance's properties, with zero set at absolute zero.
Since 2019, the kelvin has been defined by fixing the Boltzmann constant at an exact value, tying it to a fundamental physical constant rather than the triple point of water used previously.
Historical origin. Kelvin was not the invention of a single named person; it developed through the process described above.
Kelvin — sources
- BIPM — The kelvin (SI base unit) — Current definition and history of the kelvin.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many kelvins are in 1 rankine?
1 rankine equals 0.5555555556 kelvins, using the offset temperature formula rather than an estimate.
How do I convert rankine to kelvin?
Use the formula shown above: it involves both a multiplication and an addition/subtraction because the two scales don't share a common zero point.
How do I convert kelvin back to rankine?
Use the reverse factor: 1 kelvin equals 1.8 rankines. You can also use the swap control in the converter above to flip the direction instantly.
What is a rankine?
Rankine (R) is a unit of temperature.
What is a kelvin?
Kelvin (K) measures temperature. The kelvin is the SI base unit of thermodynamic temperature; 0 K (absolute zero) is the theoretical absence of thermal energy. It is classified as a SI base unit.
Is the Rankine to Kelvin conversion exact?
Yes. Both scales are formally defined relative to the Kelvin scale, so the conversion formula is exact — the only rounding involved is in how many decimal places you choose to display.