Convert Reaumur (°r) to Celsius (°C) instantly.
About these units
Reaumur (°r)
The Réaumur scale, created by René Antoine Ferchault de Réaumur in 1730, was once a major temperature scale in Europe, particularly in France, Germany, Russia, and parts of Italy. It sets the freezing point of water at 0°r and the boiling point at 80°r, giving it eighty divisions between these points. Réaumur's scale was historically used in cheese-making, brewing, confectionery, textile production, and early scientific experiments. Many recipes and industrial methods from the 18th and 19th centuries reference it. The scale's smaller numeric range made it easy to work with, though it offered less granularity than Celsius. Eventually, the Celsius scale replaced Réaumur almost everywhere due to metric standardization. However, the Réaumur scale's legacy persists in historical documents, culinary traditions, and scientific literature from the Enlightenment era, where it formed a cornerstone of early temperature standardization.
Celsius (°C)
The Celsius scale is one of the world's most widely used temperature scales, rooted in human experience and environmental observation. Defined so that water freezes at 0°C and boils at 100°C under standard atmospheric pressure, the scale provides intuitive benchmarks that align closely with everyday life, weather reporting, cooking, and basic heating or cooling applications. In scientific work, the Celsius scale aligns neatly with the kelvin: T(K) = T(°C) + 273.15, which preserves temperature intervals and ensures compatibility with thermodynamic equations. This makes Celsius suitable for most laboratory temperature measurements while maintaining convenience for ordinary use. Historically, the scale was reversed—originally, 0°C represented water's boiling point and 100°C its freezing point. It was later inverted to match modern intuitive expectations and became standardized internationally. Today, Celsius serves as a bridge between everyday perception and scientific rigor, striking a balance between practicality and precision.