Convert Rankine (°R) to Kelvin (K) instantly. Enter any value and get the result immediately.
°R → K Converter
| Rankine (°R) | Kelvin (K) |
|---|---|
| 0.1 °R | 0.05555556 K |
| 0.5 °R | 0.27777778 K |
| 1 °R | 0.55555556 K |
| 2 °R | 1.11111111 K |
| 5 °R | 2.77777778 K |
| 10 °R | 5.55555556 K |
| 20 °R | 11.11111111 K |
| 50 °R | 27.77777778 K |
| 100 °R | 55.55555556 K |
| 200 °R | 111.11111111 K |
| 500 °R | 277.77777778 K |
| 1000 °R | 555.55555556 K |
| 5000 °R | 2777.77777778 K |
| 10000 °R | 5555.55555556 K |
Both Rankine and Kelvin start at absolute zero — so no addition or subtraction needed. Just divide by 1.8:
Why 5/9? Because Rankine uses Fahrenheit-sized degrees and Kelvin uses Celsius-sized degrees. Since 1°C = 1.8°F, it follows that 1 K = 1.8°R — so to go from Rankine to Kelvin you divide by 1.8 (or multiply by 5/9).
Examples:
Rankine (°R) is an absolute temperature scale proposed by Scottish engineer William John Macquorn Rankine in 1859. Like Kelvin, it starts at absolute zero (0°R). Unlike Kelvin, it uses Fahrenheit-sized degrees, making each Rankine degree smaller than a Kelvin degree. Rankine is primarily used in US engineering thermodynamics — particularly in aerospace, HVAC, and steam power systems. The famous Rankine Cycle used in steam turbines is named after him.
Kelvin (K) is the SI base unit of temperature and the international scientific standard. Named after British physicist Lord Kelvin (William Thomson), it also starts at absolute zero (0 K). Kelvin uses Celsius-sized degrees — larger than Rankine degrees. It does not use the degree symbol (°) — written simply as "K". Kelvin is used in all scientific fields worldwide including physics, chemistry, astronomy, and engineering.
| Rankine (°R) | Kelvin (K) | Reference Point |
|---|---|---|
| 0 °R | 0 K | Absolute zero (same in both!) |
| 1 °R | 0.5556 K | Basic conversion reference |
| 7.2 °R | 4 K | Liquid helium temperature |
| 138.6 °R | 77 K | Liquid nitrogen temperature |
| 459.67 °R | 255.37 K | 0°F (Fahrenheit zero) |
| 491.67 °R | 273.15 K | Freezing point of water |
| 527.67 °R | 293.15 K | Room temperature |
| 558.27 °R | 310.15 K | Normal body temperature |
| 671.67 °R | 373.15 K | Boiling point of water |
| 1800 °R | 1000 K | Industrial furnace |
| 10,400.4 °R | 5778 K | Surface of the Sun |
| Feature | Rankine (°R) | Kelvin (K) |
|---|---|---|
| Proposed by | W.J.M. Rankine, 1859 | Lord Kelvin, 1848 |
| Type | Absolute scale | Absolute scale |
| Absolute zero | 0 °R | 0 K |
| Degree size | Same as Fahrenheit | Same as Celsius |
| Degree symbol | Yes (°R) | No (just K) |
| Can be negative? | No | No |
| Freezing point of water | 491.67 °R | 273.15 K |
| Boiling point of water | 671.67 °R | 373.15 K |
| Conversion | K × 1.8 | °R ÷ 1.8 |
| Primary use | US Engineering | Science worldwide |
The formula is: K = °R × 5/9 (same as K = °R ÷ 1.8). Example: 491.67°R × 5/9 = 273.15 K.
491.67°R = 273.15 K. This is the freezing point of water. Formula: 491.67 × 5/9 = 273.15 K.
671.67°R = 373.15 K. This is the boiling point of water at sea level. Formula: 671.67 × 5/9 = 373.15 K.
0°R = 0 K. Both scales start at absolute zero — so 0 Rankine and 0 Kelvin are exactly the same temperature. This is the coldest possible temperature in the universe.
1°R = 0.5556 K. Rankine degrees are smaller than Kelvin degrees because Rankine uses Fahrenheit-sized degrees. Formula: 1 × 5/9 = 0.5556 K.
Both are absolute scales starting at 0 (absolute zero). Kelvin uses Celsius-sized degrees and is the global scientific standard. Rankine uses Fahrenheit-sized degrees and is used in US engineering. The relation is: 1 K = 1.8°R.