Convert Megakelvin to Réaumur
Convert megakelvins to degrees réaumur instantly. °Ré = (MK × 800000) − 218.52 — use the live calculator, the exact formula, a reference-temperature table and worked examples. Also check the Réaumur to Megakelvin converter for the reverse conversion.
Units explained
Megakelvin
One megakelvin (MK) is one million kelvins (10⁶ K).
Formed with the SI prefix 'mega-' (from Greek 'megas', great) applied to the kelvin base unit.
Astrophysics and fusion science — the Sun's core burns at about 15.7 MK, and the solar corona runs at 1–3 MK.
The mega- prefix dates to the 1873 British Association system and entered the SI in 1960.
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.
Megakelvin to Réaumur conversion formula
The exact relationship between megakelvins and degrees réaumur:
To convert megakelvins to degrees réaumur, multiply the value by 800000, then subtract 218.52. To reverse, add 218.52 to the value, then multiply by 1.25e-6.
Reference anchors: water freezes at 0.00027315 MK = 0 °Ré and boils at 0.00037315 MK = 80 °Ré (at standard atmospheric pressure).
How to use this converter
Type a value into the calculator. The result in degrees réaumur updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Réaumur to Megakelvin converter for the reverse direction.
Step-by-step: convert megakelvins to degrees réaumur
- Write down the temperature in megakelvins (MK).
- Multiply the value by 800000, then subtract 218.52.
- The result is the same temperature expressed in degrees réaumur (°Ré).
- To reverse, add 218.52 to the value, then multiply by 1.25e-6 — or open the Réaumur to Megakelvin converter.
Worked examples
Example 1 — Convert 1 MK to °Ré:
(1 × 800000) − 218.52 = 799781.48 °Ré
Example 2 — Convert 100 MK to °Ré:
(100 × 800000) − 218.52 = 7.999978e+7 °Ré
Megakelvin to Réaumur conversion table
Physically meaningful reference temperatures, from absolute zero to the surface of the Sun, converted from megakelvins to degrees réaumur:
| Megakelvin [MK] | Réaumur [°Ré] | Reference point |
|---|---|---|
| 0 | -218.52 | Absolute zero |
| 0.00023315 | -32 | Where Celsius and Fahrenheit coincide (−40°) |
| 0.0002553722 | -14.2222222222 | Zero Fahrenheit (0 °F) |
| 0.00027315 | 0 | Water freezes (0 °C / 32 °F) |
| 0.00027316 | 0.008 | Triple point of water |
| 0.00028315 | 8 | Cool day (10 °C / 50 °F) |
| 0.00029315 | 16 | Room temperature (20 °C / 68 °F) |
| 0.00029815 | 20 | Standard laboratory temperature (25 °C) |
| 0.00030315 | 24 | Hot day (30 °C / 86 °F) |
| 0.00031015 | 29.6 | Human body temperature (37 °C / 98.6 °F) |
| 0.00031315 | 32 | Heat-wave day (40 °C / 104 °F) |
| 0.00032315 | 40 | Hot tap water (50 °C / 122 °F) |
| 0.00037315 | 80 | Water boils (100 °C / 212 °F) |
| 0.00045315 | 144 | Moderate baking oven (180 °C / 356 °F) |
| 0.005778 | 4403.88 | Surface of the Sun (≈5,505 °C) |
Frequently asked questions
What is 1 MK in °Ré?
How do I convert megakelvins to degrees réaumur?
How do I convert degrees réaumur back to megakelvins?
At what temperature do the Megakelvin and Réaumur scales read the same number?
Can a temperature be below absolute zero?
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Sources & references
Conversion relationship (°Ré = (MK × 800000) − 218.52) 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.