The **Réaumur temperature scale****(°Ré**), named after René Antoine Ferchault de Réaumur, a French scientist of the 18th century, is one of several historical temperature scales.

## Calculator

All information is without guarantee

**Use calculator:**

- Enter the number of Réaumur in the calculator.
- Select the temperature into which the Réaumur should be converted.
- Click on

Although it is now largely obsolete, it is occasionally found in older literature or in certain specialist areas. In this scale, water freezes at 0 °Ré and boils at 80 °Ré.

## Réaumur to Celsius

The conversion from the Réaumur scale to the Celsius scale is relatively simple, as both scales have the same zero point (the freezing point of water). The formula is: **°C = (5/4) × °Ré**

Example: To convert 20°Ré to degrees Celsius: 20 °Ré = (5/4) × 20 = 25°C

## Réaumur to Fahrenheit

The conversion from Réaumur to Fahrenheit requires an intermediate step using the Celsius scale:

1. first the temperature is converted from Réaumur to Celsius.

2. then the Celsius temperature is converted to Fahrenheit.

The formulas are:

**°C = (5/4) × °Ré****°F = °C × (5/4) 32**

Combined, this results in

**°F = ((9/5) × (5/4) × °Ré) 32**

Example: To convert 20 °Ré to Fahrenheit: 20 °Ré = ((9/5) × (5/4) × 20) 32 = 77 °F

## Réaumur in Kelvin

Here, too, you can use the Celsius scale:

1. first convert the temperature from Réaumur to Celsius.

2. then convert the Celsius temperature to Kelvin.

The formulas are:

**°C = (5/4) × °Ré****K = °C 273.15**

Combined:

**K = ((5/4) × °Ré) 273.15**

Example: To convert 20°Ré to Kelvin: 20 °Ré = ((5/4) × 20) 273.15 = 298.15 K

## Conclusion

Although the Réaumur scale is no longer in use today, it is still interesting and useful to know its relationship to the more modern temperature scales. Using the above formulas, the Réaumur temperature can easily be converted to other commonly used scales.