Convert Millikelvin to Rømer
Convert millikelvins to degrees rømer instantly. °Rø = (mK × 0.000525) − 135.90375 — use the live calculator, the exact formula, a reference-temperature table and worked examples. Also check the Rømer to Millikelvin converter for the reverse conversion.
Units explained
Millikelvin
One millikelvin (mK) is one thousandth of a kelvin (10⁻³ K), measured upward from absolute zero.
Formed with the SI prefix 'milli-' (from Latin 'mille', a thousand) applied to the kelvin base unit.
Cryogenics and low-temperature physics — the dilution refrigerators that cool superconducting quantum computers operate at roughly 10–20 mK.
The milli- prefix belongs to the original metric system of 1795 and was carried into the SI in 1960; the kelvin became an SI base unit in 1954.
Rømer
The degree Rømer (°Rø) sets the freezing point of water at 7.5 °Rø and the boiling point at 60 °Rø; one degree Rømer equals exactly 40/21 of a kelvin (about 1.905 K).
Created by Danish astronomer Ole Rømer — famous for making the first quantitative measurement of the speed of light — who set 0 °Rø at the temperature of a salt-ice brine and 60 °Rø at boiling water.
Of historical rather than practical importance: it is remembered as the direct ancestor of the Fahrenheit scale and appears mainly in the history of science and in metrology coursework.
Devised by Ole Rømer in Copenhagen, Denmark, in 1701; Daniel Fahrenheit visited Rømer in 1708 and adapted this scale into his own.
Millikelvin to Rømer conversion formula
The exact relationship between millikelvins and degrees rømer:
To convert millikelvins to degrees rømer, multiply the value by 0.000525, then subtract 135.90375. To reverse, multiply the value by 1904.761905, then add 258864.2857142857.
Reference anchors: water freezes at 273150 mK = 7.5 °Rø and boils at 373150 mK = 60 °Rø (at standard atmospheric pressure).
How to use this converter
Type a value into the calculator. The result in degrees rømer updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Rømer to Millikelvin converter for the reverse direction.
Step-by-step: convert millikelvins to degrees rømer
- Write down the temperature in millikelvins (mK).
- Multiply the value by 0.000525, then subtract 135.90375.
- The result is the same temperature expressed in degrees rømer (°Rø).
- To reverse, multiply the value by 1904.761905, then add 258864.2857142857 — or open the Rømer to Millikelvin converter.
Worked examples
Example 1 — Convert 1 mK to °Rø:
(1 × 0.000525) − 135.90375 = -135.903225 °Rø
Example 2 — Convert 100 mK to °Rø:
(100 × 0.000525) − 135.90375 = -135.85125 °Rø
Millikelvin to Rømer conversion table
Physically meaningful reference temperatures, from absolute zero to the surface of the Sun, converted from millikelvins to degrees rømer:
| Millikelvin [mK] | Rømer [°Rø] | Reference point |
|---|---|---|
| 0 | -135.90375 | Absolute zero |
| 233150 | -13.5 | Where Celsius and Fahrenheit coincide (−40°) |
| 255372.2222222222 | -1.8333333333 | Zero Fahrenheit (0 °F) |
| 273150 | 7.5 | Water freezes (0 °C / 32 °F) |
| 273160 | 7.50525 | Triple point of water |
| 283150 | 12.75 | Cool day (10 °C / 50 °F) |
| 293150 | 18 | Room temperature (20 °C / 68 °F) |
| 298150 | 20.625 | Standard laboratory temperature (25 °C) |
| 303150 | 23.25 | Hot day (30 °C / 86 °F) |
| 310150 | 26.925 | Human body temperature (37 °C / 98.6 °F) |
| 313150 | 28.5 | Heat-wave day (40 °C / 104 °F) |
| 323150 | 33.75 | Hot tap water (50 °C / 122 °F) |
| 373150 | 60 | Water boils (100 °C / 212 °F) |
| 453150 | 102 | Moderate baking oven (180 °C / 356 °F) |
| 5778000 | 2897.54625 | Surface of the Sun (≈5,505 °C) |
Frequently asked questions
What is 1 mK in °Rø?
How do I convert millikelvins to degrees rømer?
How do I convert degrees rømer back to millikelvins?
At what temperature do the Millikelvin and Rømer scales read the same number?
Can a temperature be below absolute zero?
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Scientific & Fixed-Point (3 units)
SI Prefixed Kelvin (4 units)
Sources & references
Conversion relationship (°Rø = (mK × 0.000525) − 135.90375) 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.