Fahrenheit to Réaumur (°F to °Ré)
1 degree Fahrenheit equals -13.77777778 degrees Réaumur.
How to convert degrees Fahrenheit to degrees Réaumur
Converting degrees Fahrenheit to degrees Réaumur is not a simple multiplication, so use the formula below.
°Ré = °F × 0.4444444444 − 14.22222222
Example: 10 degrees Fahrenheit = -9.777777778 degrees Réaumur.
Temperature scales have different zero points, so converting is not just multiplication. Differences in degrees convert differently from absolute readings.
About these units
Degree Fahrenheit (°F)
The temperature scale used in the United States and a few other countries: water freezes at 32 °F and boils at 212 °F. Proposed by Daniel Gabriel Fahrenheit in 1724.
Daniel Gabriel Fahrenheit, who lived from 1686 to 1736, proposed his scale in 1724. His zero came from a freezing mixture of ice, water and ammonium chloride (or sea salt), which holds a stable temperature, and his upper reference of about 96 was his estimate of human body temperature. His own letters say he built on Ole Rømer's scale. Accounts of how he picked zero differ, and a popular German story that it was the coldest winter day in his home city of Danzig has failed verification.
Around 1776 to 1777 a Royal Society committee led by Henry Cavendish fixed water's freezing point at 32 degrees and its boiling point at 212, exactly 180 degrees apart, which moved body temperature to about 98.6. Today the scale is defined through the kelvin; NIST puts absolute zero at minus 459.67 degrees Fahrenheit. It remains in everyday use in the United States and its territories, Palau, the Federated States of Micronesia, the Marshall Islands and the Cayman Islands. A comfortable room is around 70 degrees, which is about 21 degrees Celsius.
0 degrees Fahrenheit = 255.3722222 kelvins (approximately).
Sources: Wikipedia: Fahrenheit; NIST: the kelvin and the SI redefinition; NIST Guide to the SI, Appendix B.8: conversion factors
Degree Réaumur (°Ré)
A scale proposed in 1730 by René Réaumur in which water freezes at 0° and boils at 80°. Used across Europe until the 19th century and in Russia until the early 20th.
René Antoine Ferchault de Réaumur proposed a thermometer scale in 1730, and it still carries his name. He placed zero at the melting point of water and divided the tube so that each degree was one thousandth of the volume of the bulb and stem below the zero mark. His liquid was diluted alcohol, mixed so that it began to boil after expanding by 8 percent, which gave the familiar 80 degrees for boiling water. The method is also called the octogesimal division.
Instrument makers often filled their tubes with other liquids while still marking 80 for boiling water, which caused real confusion until mercury became nearly universal from the late 18th century, following Jean-André Deluc's tests in 1772. The scale was common in France, Germany and Russia, and appears in the writing of Jefferson, Dostoevsky and Tolstoy. France moved to the centigrade scale in the 1790s, but Réaumur readings lingered in parts of Europe until at least the mid-19th century and in parts of Russia into the early 20th.
Because the interval from freezing to boiling is 80 degrees instead of 100, one degree Réaumur equals 1.25 degrees Celsius, so Celsius is the Réaumur reading times 5/4. Kelvin is that figure plus 273.15. Today the scale survives mainly among some Italian and Swiss cheesemakers, who use it for milk temperatures.
0 degrees Réaumur = 273.15 kelvins (exactly).
Sources: Wikipedia: Réaumur scale
Related conversions
- Réaumur to Fahrenheit (reverse)
- Fahrenheit to kelvin
- Fahrenheit to Celsius
- Fahrenheit to Rankine
- Fahrenheit to Delisle
- Fahrenheit to Newton
- Fahrenheit to Rømer
- Kelvin to Réaumur
- Celsius to Réaumur
See all temperature units.