Instant · Precise · Universal
6 units available
6 categories total
To Celsius: °C = °Ré × 5/4. To Fahrenheit: °F = °Ré × 9/4 + 32. To Kelvin: K = °Ré × 5/4 + 273.15.
1 °Ré = 1.25 °C. The Réaumur scale divides the freezing-to-boiling range of water into 80 degrees instead of 100.
For example, 1 Réaumur (°Ré) = 274.4 Kelvin (K).
| Réaumur (°Ré) | Kelvin (K) |
|---|---|
| 0.1 | 273.275 |
| 0.5 | 273.775 |
| 1 | 274.4 |
| 2 | 275.65 |
| 5 | 279.4 |
| 10 | 285.65 |
| 25 | 304.4 |
| 50 | 335.65 |
| 100 | 398.15 |
| 500 | 898.15 |
| 1000 | 1523.15 |
The degree Réaumur is a historical temperature scale where water freezes at 0 °Ré and boils at 80 °Ré at standard pressure.
1 °Ré = 1.25 °C. The Réaumur scale divides the freezing-to-boiling range of water into 80 degrees instead of 100.
To Celsius: °C = °Ré × 5/4. To Fahrenheit: °F = °Ré × 9/4 + 32. To Kelvin: K = °Ré × 5/4 + 273.15.
Some traditional Italian pasta and cheese production references still mention Réaumur temperatures from historical recipes.
Réaumur used an alcohol-based thermometer, not mercury. Russia used the Réaumur scale as its standard until the early 20th century.
Confusing °Ré with °R (Rankine) — they are entirely different scales. Always use the full abbreviation °Ré.
Think of Réaumur as 'Celsius with 80 divisions instead of 100.' Multiply Réaumur by 1.25 to get Celsius.
The kelvin is the SI base unit of thermodynamic temperature, defined by fixing the Boltzmann constant at exactly 1.380649 × 10⁻²³ J/K. Zero kelvin (0 K) is absolute zero.
K = °C + 273.15. The kelvin scale starts at absolute zero (0 K = −273.15 °C). Same degree size as Celsius.
To Celsius: °C = K − 273.15. To Fahrenheit: °F = (K − 273.15) × 9/5 + 32. To Rankine: °R = K × 9/5.
Color temperature of lights (e.g., 2700 K warm white, 6500 K daylight), cryogenics, and engineering thermodynamics.
The cosmic microwave background radiation has a temperature of 2.725 K. The surface of the Sun is about 5,778 K. Absolute zero has never been fully reached.
Writing '°K' instead of 'K' — kelvin never uses a degree sign. Also, confusing 0 K with 0 °C.
Kelvin = Celsius + 273.15. There are no negative kelvins (in classical physics). Absolute zero (0 K) is the theoretical minimum temperature.



© 2026 UntangleTools. All Rights Reserved.