Celsius is a temperature scale with water freezing at 0 C and boiling at 100 C.
Celsius to Reaumurs Converter — C to Re
Convert Celsius (C) to Reaumur (Re) using the exact temperature formula. See the formula, worked examples, conversion table, history, and common uses.
Celsius to Reaumurs converter
Converter
Temperature Converter
Convert Celsius, Fahrenheit, Kelvin, Rankine, Delisle, Newton, Reaumur, and Romer.
Context values
Some unit families need one extra value for a physically accurate result.
Reaumur is a historical temperature scale.
Convert the source temperature to Kelvin, then convert Kelvin to the target scale.
Temperature conversion uses Kelvin as the intermediate absolute scale.
Reserved above the conversion cards and below the converter.
About Converting Celsius to Reaumurs
Celsius is a widely used everyday temperature scale, while Reaumur is a historical temperature scale no longer in common use — this conversion is mainly useful for historical reference or comparing older scientific texts against modern figures.
Formula
Convert the source temperature to Kelvin, then convert Kelvin to the target scale.
Both scales are converted through Kelvin as a common absolute reference point.
Simple example
(0 × 9/5) + 32 = 0 °F
0 celsius = 0 reaumurs.
Real-world example
(0 × 9/5) + 32 = 0 °F
0 celsius = 0 reaumurs.
Conversion table
| Celsius (C) | Reaumur (Re) |
|---|---|
| -40 C | -32 Re |
| -20 C | -16 Re |
| 0 C | 0 Re |
| 20 C | 16 Re |
| 37 C | 29.6 Re |
| 100 C | 80 Re |
Reverse conversion: Reaumur to Celsius
(0.8 − 32) × 5/9 = 1 °C
0.8 reaumurs = 1 celsius.
Convert the source temperature to Kelvin, then convert Kelvin to the target scale.
For a page dedicated to this direction, see Reaumur to Celsius.
Understanding the Celsius
Celsius (C) measures temperature. Celsius is defined relative to the Kelvin scale, with 0 °C set at 273.15 K. It is classified as a SI-derived temperature scale.
Where it's used: Standard temperature scale in nearly every country except the United States
Uses of the Celsius today
- Weather forecasting and climate reporting worldwide
- Scientific and laboratory temperature measurement (alongside Kelvin)
- Cooking and food safety in most countries outside the US
History of the Celsius
Swedish astronomer Anders Celsius proposed a 100-point temperature scale in 1742, but his original scale ran in the opposite direction, with 0° at water's boiling point and 100° at freezing.
The scale was reversed to its modern orientation shortly after his death, commonly attributed to instrument maker Daniel Ekström and naturalist Carl Linnaeus around 1744-1745.
The scale was renamed from 'centigrade' to 'Celsius' by international agreement in 1948, and it is now formally defined as the Kelvin scale shifted by 273.15, rather than independently by the freezing and boiling points of water.
Historical origin. Celsius was not the invention of a single named person; it developed through the process described above.
Understanding the Reaumur (Re)
Reaumur is a historical temperature scale.
Celsius — sources
- BIPM SI Brochure — Celsius temperature scale — Formal definition tying Celsius to Kelvin.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many reaumurs are in 1 celsius?
1 celsius equals 0.8 reaumurs, using the offset temperature formula rather than an estimate.
How do I convert celsius to reaumur?
Use the formula shown above: it involves both a multiplication and an addition/subtraction because the two scales don't share a common zero point.
How do I convert reaumur back to celsius?
Use the reverse factor: 1 reaumur equals 1.25 celsius. You can also use the swap control in the converter above to flip the direction instantly.
What is a celsius?
Celsius (C) measures temperature. Celsius is defined relative to the Kelvin scale, with 0 °C set at 273.15 K. It is classified as a SI-derived temperature scale.
What is a reaumur?
Reaumur (Re) is a unit of temperature.
Is the Celsius to Reaumur conversion exact?
Yes. Both scales are formally defined relative to the Kelvin scale, so the conversion formula is exact — the only rounding involved is in how many decimal places you choose to display.
Where is the celsius still used today?
Standard temperature scale in nearly every country except the United States