Enter value in K:
Formula: K × 9⁄5
Welcome to the Easy Converters Kelvin to Rankine Converter – your simple, fast, and reliable tool to convert temperatures from the Kelvin (K) scale to the Rankine (°R) scale. This conversion is essential for thermodynamic engineering, aerospace science, and any discipline involving absolute temperature calculations in imperial or SI units.
Kelvin (K) is the SI base unit of temperature, widely used in scientific and engineering contexts. It starts at absolute zero (0 K), where all molecular motion stops. Unlike Celsius or Fahrenheit, Kelvin does not include the term “degrees” and directly relates to energy scales in physics.
Rankine (°R) is an absolute temperature scale used mainly in the United States, especially in thermodynamic and aerospace calculations. It starts at absolute zero like Kelvin, but uses Fahrenheit-sized increments rather than Celsius-sized ones.
The formula to convert Kelvin to Rankine is:
°R = K × 1.8Example: Convert 300 K to °R:
°R = 300 × 1.8 = 540°R| Kelvin (K) | Rankine (°R) | Description |
|---|---|---|
| 0 K | 0 °R | Absolute Zero |
| 273.15 K | 491.67 °R | Freezing Point of Water |
| 300 K | 540 °R | Room Temperature |
| 373.15 K | 671.67 °R | Boiling Point of Water |
| 5778 K | 10400.4 °R | Surface of the Sun |
| Kelvin | Rankine |
|---|---|
| 100 | 180 °R |
| 200 | 360 °R |
| 300 | 540 °R |
| 400 | 720 °R |
| 500 | 900 °R |
Python:
def kelvin_to_rankine(kelvin):
return round(kelvin * 1.8, 2)
print(kelvin_to_rankine(300)) # Output: 540.0
JavaScript:
function kelvinToRankine(k) {
return (k * 1.8).toFixed(2);
}
console.log(kelvinToRankine(300)); // Output: "540.00"
K = °R / 1.8The Rankine scale was proposed in 1859 by Scottish engineer William John Macquorn Rankine. It was designed as an absolute temperature scale based on Fahrenheit intervals, offering engineers in the imperial system a way to perform thermodynamic calculations without using Celsius-based Kelvin. It complements the Kelvin scale, which had been introduced earlier by William Thomson (Lord Kelvin).
| Property | Kelvin (K) | Rankine (°R) |
|---|---|---|
| Zero Point | Absolute Zero (0 K) | Absolute Zero (0 °R) |
| Interval Size | Same as Celsius | Same as Fahrenheit |
| Used In | SI Units / Global Science | Imperial Engineering (US) |
| Water Freezing Point | 273.15 K | 491.67 °R |
| Water Boiling Point | 373.15 K | 671.67 °R |
Although Kelvin is the international standard, Rankine persists in US-centric industries that rely on the imperial system. Some of these include:
Use Rankine when:
The Sun’s surface temperature is about 5778 K. Multiply by 1.8 to convert to Rankine:
5778 × 1.8 = 10400.4 °RThat’s over ten thousand degrees Rankine!
Here’s how you’d describe this conversion in various programming languages:
Java:
public class TempConverter {
public static double kelvinToRankine(double kelvin) {
return kelvin * 1.8;
}
}
C++:
double kelvinToRankine(double kelvin) {
return kelvin * 1.8;
}
PHP:
function kelvinToRankine($kelvin) {
return round($kelvin * 1.8, 2);
}
While the basic conversion is simple multiplication, real-world use cases often demand rounding for display:
Users might also search for:
If you understand how to convert between Kelvin and Rankine, it becomes easier to grasp the structure of other temperature conversions like Celsius ↔ Fahrenheit or Kelvin ↔ Celsius. They all involve shifting zero points and scaling intervals.
Both the Kelvin and Rankine scales play essential roles in expressing the laws of thermodynamics, especially the second and third laws. Since they start at absolute zero, they allow for consistent interpretation of energy changes without the confusion of negative values.
Understanding how Rankine and Kelvin relate to other common temperature units can help users choose the right context and conversion:
| Temperature Scale | Absolute Zero | Freezing Point of Water | Boiling Point of Water |
|---|---|---|---|
| Kelvin (K) | 0 | 273.15 | 373.15 |
| Rankine (°R) | 0 | 491.67 | 671.67 |
| Celsius (°C) | -273.15 | 0 | 100 |
| Fahrenheit (°F) | -459.67 | 32 | 212 |
Rankine is often applied in high-temperature thermodynamic cycles such as the Brayton cycle or combined-cycle gas turbines. Engineers use absolute temperatures like Rankine for thermal efficiency equations, such as:
Efficiency = 1 - (T_low / T_high)Where T_low and T_high are in Rankine or Kelvin. Using absolute scales ensures accurate ratios and consistent results.
For extremely low-temperature technologies, such as superconductors, liquefied gases, and space research, Kelvin is the more commonly used unit globally. However, if pressure or enthalpy is in imperial units, Rankine becomes the standard. In cryogenics:
You don’t always need a calculator. Here are some mental math tricks:
In fields like semiconductor design and electrical resistance testing, temperature affects electron mobility and breakdown voltages. Conversions are required when equipment calibrated in Rankine needs to match theoretical models in Kelvin. For example:
Many tools like MATLAB, ANSYS, and SolidWorks require consistent unit input. If your pressure is in PSI and energy in BTU, temperature must be in Rankine. But if you’re using Pascals and Joules, Kelvin is required.
Some advanced laboratory thermometers and infrared sensors allow display toggling between Kelvin and Rankine. However, most standard consumer thermometers do not support Rankine.
| Kelvin (K) | Rankine (°R) |
|---|---|
| 0 | 0 |
| 100 | 180 |
| 273.15 | 491.67 |
| 300 | 540 |
| 373.15 | 671.67 |
| 500 | 900 |
| 1000 | 1800 |
Want to test your knowledge? Try answering these:
Answers: 1. 450 °R, 2. 666.67 K, 3. 720 °R (equal to 400 K)
Both are absolute temperature scales, but Kelvin uses Celsius-sized increments, while Rankine uses Fahrenheit-sized increments.
Yes, especially in engineering sectors within the U.S., including HVAC, aerospace, and power generation industries.
It integrates smoothly with the Imperial system, allowing for straightforward calculations using BTUs, psi, and lb mass.
Not accurately. It’s better to convert to Rankine first to maintain unit consistency in formulas.
The Kelvin to Rankine conversion is critical when working across SI and Imperial systems in temperature-based engineering disciplines. Whether you're designing propulsion systems, modeling thermal energy transfer, or performing aerospace simulations, this conversion allows for a seamless bridge between two absolute temperature standards. Use our free, fast converter to make calculations more efficient and accurate!