Temperature unit converter

Use this calculator to convert between the most common units of measure for temperature: Fahrenheit, Celsius, Kelvin, Rankine, Delisle, Newton, Réaumur and Rømer. Select the unit that you want to convert from and the one that you want to convert to.


How to use the temperature converter

Use the drop down menus to select the temperature scale that you want to convert from and the scale that you want to convert to, then press the convert button. The convert button is disabled when the same unit is chosen for both source and target scale or when the source or target has not yet been selected. Then press the Convert button. The following temperature scales are currently supported by the converter:

Fahrenheit Scale

Widely used in the United States, the Fahrenheit scale is named after Daniel Gabriel Fahrenheit, inventor of the alcohol and mercury thermometers. The freezing point of water is 32 °F, and the boiling point is 212 °F.

Celsius Scale

The Celsius scale is the most commonly used temperature scale and the standard used for most applications by the scientific community worldwide. The boiling point of water is 100 °C. The freezing point is 0 °C. The word centigrade is used in many languages to describe Celsius.

kelvin Scale

Kelvin is the unit of measure for temperature adopted by the International System of Units. Absolute zero is 0 K, equivalent to -273.15 °C. Kelvin uses the same interval as Celsius. The Kelvin scale is named after Baron Kelvin of Largs, who described the need for an absolute thermometric scale in his paper "On an Absolute Thermometric Scale".

Rankine Scale

The Rankine scale is named after Scottish physicist William John Macquorn Rankine. Similarly to kelvin absolute zero is 0 °R, equivalent to -459.67 °F. Rankine uses the same interval as Fahrenheit.

Delisle Scale

The Delisle scale places the water freezing point at 150 °D, and water boiling point at 0 °D. Therefore at higher Delisle numbers correspond lower temperatures. It was invented by Joseph-Nicolas Delisle, a French astronomer.

Newton Scale

The Newton scale, was invented by Isaac Newton. 0 °N was defined by Newton to be the temperature of melting snow and 33 °N, the temperature of boiling water.

Réaumur Scale

The Réaumur scale, named after René Antoine Ferchault de Réaumur places water freezing point at 0 °Ré and water boiling point at 80 °Ré.

Rømer Scale

The Rømer scale owes its name to it's inventor Ole Christensen Rømer. A Rømer degree is equivalent to 40/21 of a Celsius degree. It places the water freezing point at 7.5 °Rø.