Rankine to Réaumur Converter

Rankine (°R) is an absolute temperature scale that uses Fahrenheit-sized degrees but starts at absolute zero, similar to Kelvin. One degree Rankine equals one degree Fahrenheit, with 0°R being absolute zero.

The Rankine scale was developed by Scottish engineer and physicist William John Macquorn Rankine in 1859. It was created to provide an absolute temperature scale for engineering applications in countries using the Fahrenheit system, combining the familiar Fahrenheit degree size with the scientific concept of absolute zero.

Rankine is primarily used in engineering applications in the United States, particularly in thermodynamics, heat transfer calculations, and steam power systems. It's used in some specialized engineering software and textbooks, though Kelvin is increasingly preferred even in American scientific and engineering contexts.

Réaumur (°Ré or °R) is a temperature scale where 0°Ré is the freezing point of water and 80°Ré is the boiling point of water at standard atmospheric pressure. Each degree Réaumur equals 1.25 degrees Celsius.

The Réaumur scale was developed by French scientist René Antoine Ferchault de Réaumur in 1730. He chose 80 degrees between the freezing and boiling points of water because his alcohol-based thermometer expanded by 80 parts per 1000 when heated from freezing to boiling water.

The Réaumur scale is largely obsolete and rarely used today. It may occasionally appear in historical scientific documents, some traditional European recipes (particularly in Germany and Russia), and certain specialized industrial applications. Most modern applications have switched to Celsius or Fahrenheit.