🌡️ Réaumur to Celsius Converter
Instantly convert temperatures from Réaumur (°Ré) to Celsius (°C). The Réaumur scale, with 0° for the freezing point and 80° for the boiling point of water, was widely used in Europe, particularly in France and Germany, until the early 20th century.
What Is the Réaumur Scale?
The Réaumur scale (°Ré) is a temperature scale proposed by the French scientist René Antoine Ferchault de Réaumur in 1730. It was one of the most widely used temperature scales in Europe during the 18th and 19th centuries, particularly in France and Germany.
Key characteristics of the Réaumur scale:
- Zero point: 0 °Ré is the freezing point of water (0 °C).
- Boiling point: 80 °Ré is the boiling point of water (100 °C).
- Division: The interval between freezing and boiling is divided into 80 equal parts.
- Unit size: 1 degree Réaumur is equivalent to 1.25 degrees Celsius.
- Conversion formula: °C = °Ré × 5/4.
Réaumur used a diluted alcohol as the thermometric fluid in his thermometer, chosen for its consistent expansion properties. The scale was widely adopted in France and Germany, particularly in the dairy industry for measuring milk temperatures, and remained in use in some parts of Europe until the early 20th century.
How to Convert Réaumur to Celsius
The formula to convert Réaumur to Celsius is:
°C = °Ré × 5/4
or °C = °Ré × 1.25
This formula works because:
- The Réaumur scale has 80 degrees between the freezing and boiling points of water.
- The Celsius scale has 100 degrees between the same two points.
- Therefore, 1 °Ré = 100/80 = 1.25 °C.
For example, to convert 80 °Ré (the boiling point of water) to Celsius:
°C = 80 × 5/4
°C = 80 × 1.25
°C = 100 °C
Why Use This Converter?
- Instant results: Get accurate temperature conversions in real-time.
- Step-by-step breakdown: See exactly how the conversion is calculated.
- Common reference table: Quickly check temperatures from −40 °Ré to 100 °Ré.
- Free & private: No registration, no data storage — all calculations are done in your browser.
❓ Réaumur to Celsius FAQ
What is the formula to convert Réaumur to Celsius?
The formula is °C = °Ré × 5/4 or °C = °Ré × 1.25.
What is the Réaumur scale used for?
The Réaumur scale was widely used in Europe, particularly in France and Germany, during the 18th and 19th centuries. It was commonly used in the dairy industry for measuring milk temperatures and in some industrial processes.
What is the relationship between Réaumur and Celsius?
Both scales share the same zero point (the freezing point of water = 0 °Ré = 0 °C). However, the Réaumur scale divides the interval between freezing and boiling into 80 degrees, while the Celsius scale divides it into 100 degrees. Therefore, 1 °Ré = 1.25 °C.
What is absolute zero in Réaumur?
Absolute zero (−273.15 °C) is equivalent to approximately −218.52 °Ré.
What is the freezing point of water in Réaumur?
The freezing point of water (0 °C) is 0 °Ré.
What is the boiling point of water in Réaumur?
The boiling point of water (100 °C) is 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?
The Réaumur scale is largely obsolete for everyday use but is still occasionally referenced in historical studies, some European dairy industry practices, and certain engineering contexts.
How accurate is this converter?
This converter provides highly accurate results using the standard conversion formula °C = °Ré × 5/4. 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.