Convert Reaumur (°r) to Kelvin (K) 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 However, the Réaumur scale's legacy persists in historical documents, culinary traditions, and scientific literature from the Enlightenment era, where it formed a cornerstone of early temperature standardization.
Kelvin (K)
The kelvin is the base unit of temperature in the International System of Units (SI) and is unique among temperature scales because it begins at absolute zero, the theoretical point where all classical molecular motion ceases. This gives the kelvin an absolute physical foundation that other temperature scales lack. Instead of being tied to the properties of water or human experience, the kelvin reflects universal thermodynamic behavior, making it indispensable for physics, chemistry, engineering, and cosmology. One of the kelvin's strengths is that temperature differences measured in kelvins are identical to those measured in degrees Celsius, simplifying conversions in scientific work. The kelvin scale is critical for understanding entropy, thermal energy, and statistical mechanics, where temperature represents average kinetic energy of particles rather than subjective sensation. Modern definitions anchor the kelvin to a fixed numerical value of the Boltzmann constant, connecting macroscopic temperature directly to microscopic energy. This reformulation, adopted in 2019, ensures that the kelvin remains precise and universally stable across laboratories worldwide, independent of any specific material reference point. As such, the kelvin is not merely a unit of temperature—it is a gateway to the deeper physical meaning of heat and energy.