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📋 Rankine to Celsius Reference Quick conversion guide
Key Temperatures
Absolute Zero (°R)0 °R = −273.15 °C
Water Freezes (°R)491.67 °R = 0 °C
Room Temperature527.67 °R ≈ 20 °C
Water Boils (°R)671.67 °R = 100 °C
Conversion Formula
°C = (°R − 491.67) × 5/9
or °C = (°R × 5/9) − 273.15
Rankine Scale Absolute temperature scale
Unit Symbol °R
Named After William John Macquorn Rankine
Degree Size Same as Fahrenheit
Note: The Rankine scale is to the Fahrenheit scale what the Kelvin scale is to the Celsius scale. A degree Rankine is the same size as a degree Fahrenheit, but 0 °R is absolute zero (−459.67 °F).

What Is the Rankine Scale?

The Rankine scale (°R) is an absolute temperature scale named after the Scottish engineer and physicist William John Macquorn Rankine (1820–1872). It is the absolute counterpart to the Fahrenheit scale, just as the Kelvin scale is the absolute counterpart to the Celsius scale.

Key characteristics of the Rankine scale:

  • Zero point: 0 °R is absolute zero, the point at which all molecular motion stops.
  • Degree size: A degree Rankine is the same size as a degree Fahrenheit (1.8 times the size of a degree Celsius or Kelvin).
  • Freezing point of water: 491.67 °R (32 °F, 0 °C).
  • Boiling point of water: 671.67 °R (212 °F, 100 °C).
  • Conversion to Celsius: °C = (°R − 491.67) × 5/9.

The Rankine scale is commonly used in thermodynamics and engineering applications in the United States, particularly in fields like aerospace, power generation, and HVAC systems.

How to Convert Rankine to Celsius

The formula to convert Rankine to Celsius is:

°C = (°R − 491.67) × 5/9

Alternatively: °C = (°R × 5/9) − 273.15

This formula works because:

  • Subtracting 491.67 shifts the zero point from absolute zero to the Fahrenheit zero point (−459.67 °F = 0 °R).
  • Multiplying by 5/9 converts the temperature increment from Fahrenheit degrees to Celsius degrees.

For example, to convert 671.67 °R (the boiling point of water) to Celsius:

°C = (671.67 − 491.67) × 5/9

°C = 180 × 5/9

°C = 100 °C

Why Use This Converter?

  • Instant results: Get accurate conversions in real-time.
  • Step-by-step breakdown: See exactly how the conversion is calculated.
  • Common reference table: Quickly check temperatures from 0 °R to 700 °R.
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❓ Rankine to Celsius FAQ

What is the formula to convert Rankine to Celsius?

The formula is °C = (°R − 491.67) × 5/9. Alternatively, you can use °C = (°R × 5/9) − 273.15.

What is the Rankine scale used for?

The Rankine scale is used in thermodynamics and engineering, particularly in the United States, for applications like aerospace, power generation, and HVAC systems. It is the absolute temperature scale that corresponds to the Fahrenheit scale.

What is the difference between Rankine and Kelvin?

Both are absolute temperature scales, but Kelvin is based on the Celsius scale (a degree Kelvin is the same size as a degree Celsius), while Rankine is based on the Fahrenheit scale (a degree Rankine is the same size as a degree Fahrenheit). 0 K = 0 °R, but 1 K = 1.8 °R.

What is absolute zero in Celsius?

Absolute zero is −273.15 °C, which is equivalent to 0 °R, 0 K, and −459.67 °F.

What is the freezing point of water in Rankine?

Water freezes at 491.67 °R (32 °F, 0 °C).

What is the boiling point of water in Rankine?

Water boils at 671.67 °R (212 °F, 100 °C).

Who invented the Rankine scale?

The Rankine scale was invented by William John Macquorn Rankine (1820–1872), a Scottish engineer and physicist.

Is Rankine still used today?

Yes, the Rankine scale is still used in engineering and thermodynamics, particularly in the United States, for calculations involving absolute temperatures.

How accurate is this converter?

This converter provides highly accurate results using the standard conversion formula °C = (°R − 491.67) × 5/9. You can adjust the decimal precision to suit your needs.

Is this converter free?

Yes, this converter is completely free to use. No registration or personal data storage is required.