Celsius to Rankine Converter (°C to °R)

How to Convert Celsius to Rankine

The formula to convert Celsius (°C) to Rankine (°R) is:

Step-by-step example — Convert 25°C to °R:

More examples:

• 0°C → (0 + 273.15) × 1.8 = 491.67°R (freezing point of water)
• 100°C → (100 + 273.15) × 1.8 = 671.67°R (boiling point of water)
• -273.15°C → (0) × 1.8 = 0°R (absolute zero)
• 37°C → (37 + 273.15) × 1.8 = 558.27°R (body temperature)

What is Rankine?

Rankine (°R) is an absolute temperature scale proposed by Scottish engineer William John Macquorn Rankine in 1859. Like Kelvin, it starts at absolute zero — the coldest possible temperature in the universe. However, unlike Kelvin which uses Celsius-sized degrees, Rankine uses Fahrenheit-sized degrees.

This means: 1°R = 1°F in terms of degree size, but Rankine starts at absolute zero while Fahrenheit starts at -459.67°F. The relationship between Rankine and Fahrenheit is: °R = °F + 459.67

What is Celsius?

Celsius (°C) is the most widely used temperature scale globally, part of the metric system. Developed by Swedish astronomer Anders Celsius in 1742, it defines 0°C as the freezing point and 100°C as the boiling point of water at standard atmospheric pressure.

Celsius to Rankine Reference Chart

Celsius (°C)	Rankine (°R)	Reference Point
-273.15 °C	0 °R	Absolute zero
-196 °C	139.07 °R	Liquid nitrogen
0 °C	491.67 °R	Freezing point of water
20 °C	527.67 °R	Room temperature
25 °C	536.67 °R	Warm room temperature
37 °C	558.27 °R	Human body temperature
100 °C	671.67 °R	Boiling point of water
1000 °C	2291.67 °R	Molten lava
5526 °C	10,642 °R	Surface of the Sun

Rankine vs Kelvin — Key Differences

Feature	Rankine (°R)	Kelvin (K)
Absolute zero	0 °R	0 K
Degree size	Same as Fahrenheit	Same as Celsius
Freezing point of water	491.67 °R	273.15 K
Boiling point of water	671.67 °R	373.15 K
Relation	1 K = 1.8°R	1°R = 0.5556 K
Used in	US Engineering	Science worldwide

Where is Rankine Scale Used?

• Aerospace Engineering: Used in thermodynamic calculations in the US aerospace industry.
• HVAC Systems: Heating, ventilation, and air conditioning engineering in the United States.
• Steam Power Systems: Rankine Cycle — a thermodynamic cycle used in steam turbines and power plants — is named after the same scientist.
• Chemical Engineering: Some US-based chemical engineering textbooks and calculations use Rankine.

Frequently Asked Questions

What is the formula to convert Celsius to Rankine?

The formula is: °R = (°C + 273.15) × 9/5. First convert Celsius to Kelvin by adding 273.15, then multiply by 1.8.

What is 0°C in Rankine?

0°C = 491.67°R. This is the freezing point of water in the Rankine scale.

What is 100°C in Rankine?

100°C = 671.67°R. This is the boiling point of water expressed in Rankine.

What is absolute zero in Rankine?

Absolute zero is 0°R = -273.15°C. This is the theoretically coldest possible temperature in the universe.

What is the difference between Rankine and Kelvin?

Both are absolute scales starting at absolute zero. Kelvin uses Celsius-sized degrees (used in science worldwide), while Rankine uses Fahrenheit-sized degrees (used in US engineering). The relation is: 1 K = 1.8°R.

Where is the Rankine scale used?

Rankine is used primarily in US engineering thermodynamics — especially in aerospace, HVAC, and steam power systems. Most of the world uses Kelvin for scientific absolute temperature measurements.