🌡️ Celsius to Réaumur Converter
Instantly convert temperatures from Celsius (°C) to Réaumur (°Ré). The Réaumur scale is a historical temperature scale named after René Antoine Ferchault de Réaumur, with 0 °Ré at the freezing point of water and 80 °Ré at the boiling point.
What Is the Réaumur Scale?
The Réaumur scale (°Ré) is a historical temperature scale named after the French scientist René Antoine Ferchault de Réaumur (1683–1757). He proposed the scale in 1730.
Key characteristics of the Réaumur scale:
- Freezing point of water: 0 °Ré
- Boiling point of water: 80 °Ré
- Degree size: 1 degree Réaumur is 1.25 times larger than 1 degree Celsius (or Kelvin).
- Conversion to Celsius: °Ré = °C × 4/5, or °C = °Ré × 5/4.
- Historical use: Widely used in Europe, especially in France, Germany, and Russia, during the 18th and 19th centuries.
The Réaumur scale was historically popular because it aligned conveniently with the alcohol thermometers of the time. Today, it is mostly of historical interest, but it is still used in some specialized applications, particularly in certain European industries.
How to Convert Celsius to Réaumur
The formula to convert Celsius to Réaumur is:
°Ré = °C × 4/5
Alternatively: °Ré = °C × 0.8
This simple formula works because the Réaumur scale has 80 degrees between the freezing and boiling points of water, while the Celsius scale has 100 degrees. Therefore, 1 °Ré = 1.25 °C, and 1 °C = 0.8 °Ré.
For example, to convert 100 °C (the boiling point of water) to Réaumur:
°Ré = 100 × 4/5
°Ré = 100 × 0.8
°Ré = 80 °Ré
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 −40 °C to 200 °C.
- Free & private: No registration, no data storage — all calculations are done in your browser.
❓ Celsius to Réaumur FAQ
What is the formula to convert Celsius to Réaumur?
The formula is °Ré = °C × 4/5 or °Ré = °C × 0.8.
What is the Réaumur scale used for?
The Réaumur scale is a historical temperature scale that was widely used in Europe in the 18th and 19th centuries. Today, it is mostly of historical interest but is still used in some specialized applications in certain European industries.
What is the difference between Réaumur and Celsius?
Both scales use the freezing point of water as 0°, but they differ at the boiling point: 100 °C vs. 80 °Ré. This means a degree Réaumur is 1.25 times larger than a degree Celsius.
What is the freezing point of water in Réaumur?
Water freezes at 0 °Ré.
What is the boiling point of water in Réaumur?
Water boils at 80 °Ré.
Who invented the Réaumur scale?
The Réaumur scale was invented by René Antoine Ferchault de Réaumur (1683–1757), a French scientist, in 1730.
Is the Réaumur scale still used today?
It is rarely used in everyday life but can still be found in some specialized applications, particularly in certain European industries and in some historical contexts.
How accurate is this converter?
This converter provides highly accurate results using the standard conversion formula °Ré = °C × 4/5. 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.
How do I convert Réaumur back to Celsius?
To convert Réaumur to Celsius, use the formula: °C = °Ré × 5/4 or °C = °Ré × 1.25.