Convert Réaumur to Planck Temperature
Convert degrees réaumur to planck temperatures instantly. T_P = (°Ré + 218.52) × 8.822799e-33 — use the live calculator, the exact formula, a reference-temperature table and worked examples. Also check the Planck Temperature 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.
Planck Temperature
The Planck temperature (T_P) is the natural unit of temperature, about 1.416784×10³² kelvins, constructed purely from the fundamental constants ħ, c, G, and k. It is widely regarded as the highest temperature at which known physics remains meaningful.
Arises from Max Planck's 1899 system of natural units, which combines the speed of light, the gravitational constant, the reduced Planck constant, and the Boltzmann constant into universal base quantities independent of any human artifact.
Cosmology and quantum-gravity research, where it marks the temperature of the universe roughly one Planck time after the Big Bang. No laboratory process approaches even a trillionth of a trillionth of it.
Defined within Max Planck's natural-unit system proposed in Germany in 1899; the modern recommended value (1.416784×10³² K) is maintained by the CODATA fundamental-constants adjustment.
Réaumur to Planck Temperature conversion formula
Note: this conversion uses the CODATA recommended value of the Planck temperature (1.416784×10³² K), which carries a small experimental uncertainty from the gravitational constant G.
The exact relationship between degrees réaumur and planck temperatures:
To convert degrees réaumur to planck temperatures, add 218.52 to the value, then multiply by 8.822799e-33. To reverse, multiply the value by 1.133427e+32, then subtract 218.52.
Reference anchors: water freezes at 0 °Ré = 1.927958e-30 T_P and boils at 80 °Ré = 2.633782e-30 T_P (at standard atmospheric pressure).
How to use this converter
Type a value into the calculator. The result in planck temperatures updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Planck Temperature to Réaumur converter for the reverse direction.
Step-by-step: convert degrees réaumur to planck temperatures
- Write down the temperature in degrees réaumur (°Ré).
- Add 218.52 to the value, then multiply by 8.822799e-33.
- The result is the same temperature expressed in planck temperatures (T_P).
- To reverse, multiply the value by 1.133427e+32, then subtract 218.52 — or open the Planck Temperature to Réaumur converter.
Worked examples
Example 1 — Convert 29.6 °Ré to T_P (human body temperature):
(29.6 + 218.52) × 8.822799e-33 = 2.189113e-30 T_P
Example 2 — Convert 80 °Ré to T_P (the boiling point of water):
(80 + 218.52) × 8.822799e-33 = 2.633782e-30 T_P
Réaumur to Planck Temperature conversion table
Physically meaningful reference temperatures, from absolute zero to the surface of the Sun, converted from degrees réaumur to planck temperatures:
| Réaumur [°Ré] | Planck Temperature [T_P] | Reference point |
|---|---|---|
| -218.52 | 0 | Absolute zero |
| -32 | 1.645628e-30 | Where Celsius and Fahrenheit coincide (−40°) |
| -14.2222222222 | 1.802478e-30 | Zero Fahrenheit (0 °F) |
| 0 | 1.927958e-30 | Water freezes (0 °C / 32 °F) |
| 0.008 | 1.928029e-30 | Triple point of water |
| 8 | 1.99854e-30 | Cool day (10 °C / 50 °F) |
| 16 | 2.069123e-30 | Room temperature (20 °C / 68 °F) |
| 20 | 2.104414e-30 | Standard laboratory temperature (25 °C) |
| 24 | 2.139705e-30 | Hot day (30 °C / 86 °F) |
| 29.6 | 2.189113e-30 | Human body temperature (37 °C / 98.6 °F) |
| 32 | 2.210288e-30 | Heat-wave day (40 °C / 104 °F) |
| 40 | 2.28087e-30 | Hot tap water (50 °C / 122 °F) |
| 80 | 2.633782e-30 | Water boils (100 °C / 212 °F) |
| 144 | 3.198441e-30 | Moderate baking oven (180 °C / 356 °F) |
| 4403.88 | 4.07825e-29 | Surface of the Sun (≈5,505 °C) |
Frequently asked questions
What is 29.6 °Ré in T_P?
How do I convert degrees réaumur to planck temperatures?
How do I convert planck temperatures back to degrees réaumur?
At what temperature do the Réaumur and Planck Temperature scales read the same number?
Can a temperature be below absolute zero?
Popular temperature unit conversions
Convert Réaumur to other temperature units
Show all Réaumur conversions
Modern Standard Scales (4 units)
Historical Scales (3 units)
Scientific & Fixed-Point (3 units)
Sources & references
Conversion relationship (T_P = (°Ré + 218.52) × 8.822799e-33) 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.