Convert Réaumur to Electronvolt
Convert degrees réaumur to electronvolts instantly. eV = (°Ré + 218.52) × 0.0001077166658 — use the live calculator, the exact formula, a reference-temperature table and worked examples. Also check the Electronvolt to Réaumur converter for the reverse conversion.
Units explained
Réaumur
The degree Réaumur (°Ré) sets the freezing point of water at 0 °Ré and the boiling point at 80 °Ré, so one degree Réaumur equals exactly 1.25 kelvins (5/4 K).
Devised by French scientist René Antoine Ferchault de Réaumur using alcohol thermometers whose working liquid expanded 80 parts per thousand between the freezing and boiling points of water — the origin of the 80-degree span.
Once dominant across 18th- and 19th-century Europe, especially France, Germany, and Russia. It survives today mainly in traditional cheese-making — Parmigiano-Reggiano and Swiss alpine dairies still specify milk temperatures in °Ré.
Introduced by Réaumur in Paris in 1730; it faded from general use after France adopted the Celsius scale with the metric system in the 1790s.
Electronvolt
As a temperature unit, one electronvolt (eV) is the temperature at which a particle's characteristic thermal energy kT equals one electronvolt — exactly 11,604.51812 kelvins under the 2019 SI definitions of e and k.
Comes from the plasma-physics and astrophysics habit of quoting temperatures directly as energies through the Boltzmann relation E = kT, which removes constant unit conversions from the equations of hot ionized matter.
Standard in plasma physics, fusion research, and high-energy astrophysics: the core plasma of a tokamak runs at tens of kiloelectronvolts, while the Sun's core is about 1.3 keV.
Grew out of 20th-century particle- and plasma-physics convention; its kelvin equivalent became an exact number when the 2019 SI revision fixed both the elementary charge and the Boltzmann constant.
Réaumur to Electronvolt conversion formula
The exact relationship between degrees réaumur and electronvolts:
To convert degrees réaumur to electronvolts, add 218.52 to the value, then multiply by 0.0001077166658. To reverse, multiply the value by 9283.614497, then subtract 218.52.
Reference anchors: water freezes at 0 °Ré = 0.0235382458 eV and boils at 80 °Ré = 0.0321555791 eV (at standard atmospheric pressure).
How to use this converter
Type a value into the calculator. The result in electronvolts updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Electronvolt to Réaumur converter for the reverse direction.
Step-by-step: convert degrees réaumur to electronvolts
- Write down the temperature in degrees réaumur (°Ré).
- Add 218.52 to the value, then multiply by 0.0001077166658.
- The result is the same temperature expressed in electronvolts (eV).
- To reverse, multiply the value by 9283.614497, then subtract 218.52 — or open the Electronvolt to Réaumur converter.
Worked examples
Example 1 — Convert 29.6 °Ré to eV (human body temperature):
(29.6 + 218.52) × 0.0001077166658 = 0.0267266591 eV
Example 2 — Convert 80 °Ré to eV (the boiling point of water):
(80 + 218.52) × 0.0001077166658 = 0.0321555791 eV
Réaumur to Electronvolt conversion table
Physically meaningful reference temperatures, from absolute zero to the surface of the Sun, converted from degrees réaumur to electronvolts:
| Réaumur [°Ré] | Electronvolt [eV] | Reference point |
|---|---|---|
| -218.52 | 0 | Absolute zero |
| -32 | 0.0200913125 | Where Celsius and Fahrenheit coincide (−40°) |
| -14.2222222222 | 0.0220062754 | Zero Fahrenheit (0 °F) |
| 0 | 0.0235382458 | Water freezes (0 °C / 32 °F) |
| 0.008 | 0.0235391075 | Triple point of water |
| 8 | 0.0243999791 | Cool day (10 °C / 50 °F) |
| 16 | 0.0252617125 | Room temperature (20 °C / 68 °F) |
| 20 | 0.0256925791 | Standard laboratory temperature (25 °C) |
| 24 | 0.0261234458 | Hot day (30 °C / 86 °F) |
| 29.6 | 0.0267266591 | Human body temperature (37 °C / 98.6 °F) |
| 32 | 0.0269851791 | Heat-wave day (40 °C / 104 °F) |
| 40 | 0.0278469124 | Hot tap water (50 °C / 122 °F) |
| 80 | 0.0321555791 | Water boils (100 °C / 212 °F) |
| 144 | 0.0390494457 | Moderate baking oven (180 °C / 356 °F) |
| 4403.88 | 0.4979095159 | Surface of the Sun (≈5,505 °C) |
Frequently asked questions
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At what temperature do the Réaumur and Electronvolt scales read the same number?
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Scientific & Fixed-Point (3 units)
Sources & references
Conversion relationship (eV = (°Ré + 218.52) × 0.0001077166658) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- BIPM — International Temperature Scale of 1990 (ITS-90)
The internationally agreed practical temperature scale, defining fixed points (including the triple point of water at 273.16 K) and interpolation instruments used by national metrology institutes for thermometer calibration worldwide.
- CODATA Internationally Recommended Values of the Fundamental Physical Constants
Committee on Data of the International Science Council; authoritative source for the masses of fundamental particles (electron, proton, neutron) and the atomic mass constant.