Kelvin to Rankine Converter

Kelvin (K)

Rankine (°R)

°R

Quick Conversions:

Conversion Formula

°R = K × 9/5

The temperature in degrees Rankine (°R) equals the temperature in Kelvin (K) multiplied by 9/5 (or 1.8).

Example Calculation:

Convert 300 K to Rankine:

°R = 300 × (9/5)

°R = 300 × 1.8

°R = 540 °R

Step-by-Step Conversion Process

Take your temperature value in Kelvin
Multiply the Kelvin value by 9
Divide the result by 5 (alternatively, multiply by 1.8)
The result is your temperature in degrees Rankine

Example 2:

Convert 100 K to Rankine:

Step 1: 100 × 9 = 900

Step 2: 900 ÷ 5 = 180 °R

Example 3:

Convert 273.15 K (freezing point of water) to Rankine:

°R = 273.15 × 1.8

°R = 491.67 °R

Conversion Chart

Kelvin (K)	Rankine (°R)

Popular Kelvin to Rankine Conversions

Description	Kelvin (K)	Rankine (°R)
Absolute Zero	0 K	0 °R
Freezing Point of Water	273.15 K	491.67 °R
Triple Point of Water	273.16 K	491.688 °R
Room Temperature	293.15 K	527.67 °R
Human Body Temperature	310.15 K	558.27 °R
Boiling Point of Water	373.15 K	671.67 °R

About Kelvin Scale

The Kelvin scale serves as an absolute temperature scale using absolute zero as its starting point. Named after physicist William Thomson, 1st Baron Kelvin, this scale represents one of the seven SI base units in the metric system.

Key Characteristics of Kelvin

Symbol: K (not °K – no degree symbol is used)
Absolute Zero: 0 K (the lowest possible temperature)
Freezing Point of Water: 273.15 K
Boiling Point of Water: 373.15 K
No Negative Values: The scale starts at absolute zero
Scientific Standard: Widely used in scientific and engineering applications

The Kelvin is defined in terms of the Boltzmann constant, which measures the energy of motion corresponding to one kelvin. Specifically, one kelvin equals the change of thermodynamic temperature resulting in a change of thermal energy kT by 1.380649 × 10⁻²³ joules.

About Rankine Scale

The Rankine scale represents an absolute temperature scale similar to Kelvin but uses Fahrenheit-sized degrees. Named after Scottish engineer and physicist William John Macquorn Rankine, this scale is primarily used in engineering applications in the United States.

Key Characteristics of Rankine

Symbol: °R (sometimes Ra)
Absolute Zero: 0 °R (equals -459.67 °F)
Freezing Point of Water: 491.67 °R
Boiling Point of Water: 671.67 °R
No Negative Values: Starts at absolute zero like Kelvin
Relationship to Fahrenheit: One degree Rankine equals one degree Fahrenheit

The Rankine scale combines the absolute nature of the Kelvin scale with the familiar Fahrenheit degree intervals, making it particularly useful in certain engineering calculations where Fahrenheit is commonly used.

Related Temperature Conversions

Frequently Asked Questions

How do you convert Kelvin to Rankine?

To convert Kelvin to Rankine, multiply the Kelvin value by 9/5 (or 1.8). The formula is: °R = K × 1.8. For example, 300 K equals 540 °R (300 × 1.8 = 540).

Why do Kelvin and Rankine both start at absolute zero?

Both Kelvin and Rankine are absolute temperature scales, meaning they start at absolute zero—the theoretical lowest possible temperature where molecular motion ceases. This makes them particularly useful for scientific and engineering calculations involving thermodynamics and heat transfer.

What is the relationship between Kelvin and Rankine?

The relationship between Kelvin and Rankine is linear: 1 Kelvin equals 1.8 degrees Rankine. Both scales start at absolute zero, but Rankine uses Fahrenheit-sized degrees while Kelvin uses Celsius-sized degrees. This makes the Rankine scale exactly 1.8 times the Kelvin scale.

When should I use Rankine instead of Kelvin?

Rankine is primarily used in engineering fields in the United States, particularly in thermodynamics and heat transfer calculations where Fahrenheit is the standard. Kelvin is the international standard for scientific work and is used worldwide. Choose Rankine when working in industries or regions that primarily use Fahrenheit.

Can Kelvin or Rankine have negative values?

No, neither Kelvin nor Rankine can have negative values because both scales start at absolute zero (0 K = 0 °R), which is the lowest possible temperature in the universe. Any temperature below absolute zero is physically impossible according to current scientific knowledge.

What is 273.15 K in Rankine?

273.15 K (the freezing point of water) equals 491.67 °R. This is calculated using the formula: 273.15 × 1.8 = 491.67. This temperature represents the point where water transitions from liquid to solid at standard atmospheric pressure.

How accurate is the K × 1.8 conversion method?

The K × 1.8 conversion method is mathematically exact and provides complete accuracy. Since 1.8 is precisely equal to 9/5, both methods (K × 9/5 or K × 1.8) yield identical results. The choice between them is purely a matter of calculation convenience.