Convert Millikelvin to Celsius
Convert millikelvins to degrees celsius instantly. °C = (mK × 1/1000) − 273.15 — use the live calculator, the exact formula, a reference-temperature table and worked examples. Also check the Celsius 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.
Celsius
The degree Celsius (°C) is the SI's everyday temperature unit. One degree Celsius is exactly the same size as one kelvin, with the zero point shifted so that 0 °C = 273.15 K. Water freezes near 0 °C and boils near 100 °C at standard atmospheric pressure.
Named for Swedish astronomer Anders Celsius, who in 1742 proposed a 100-degree scale between the boiling and freezing points of water. His original scale ran in reverse (0 at boiling, 100 at freezing); it was inverted to the modern direction shortly after his death.
The world's standard everyday temperature scale, used in nearly every country — including throughout India — for weather forecasts, cooking, medicine, science classrooms, and industry.
Devised by Anders Celsius at Uppsala University, Sweden, in 1742; the inverted modern form was in use by 1745, and the name 'degree Celsius' replaced 'degree centigrade' internationally at the 9th CGPM in 1948.
Millikelvin to Celsius conversion formula
The exact relationship between millikelvins and degrees celsius:
To convert millikelvins to degrees celsius, multiply the value by 1/1000, then subtract 273.15. To reverse, multiply the value by 1000, then add 273150.
Reference anchors: water freezes at 273150 mK = 0 °C and boils at 373150 mK = 100 °C (at standard atmospheric pressure).
How to use this converter
Type a value into the calculator. The result in degrees celsius updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Celsius to Millikelvin converter for the reverse direction.
Step-by-step: convert millikelvins to degrees celsius
- Write down the temperature in millikelvins (mK).
- Multiply the value by 1/1000, then subtract 273.15.
- The result is the same temperature expressed in degrees celsius (°C).
- To reverse, multiply the value by 1000, then add 273150 — or open the Celsius to Millikelvin converter.
Worked examples
Example 1 — Convert 1 mK to °C:
(1 × 1/1000) − 273.15 = -273.149 °C
Example 2 — Convert 100 mK to °C:
(100 × 1/1000) − 273.15 = -273.05 °C
Millikelvin to Celsius conversion table
Physically meaningful reference temperatures, from absolute zero to the surface of the Sun, converted from millikelvins to degrees celsius:
| Millikelvin [mK] | Celsius [°C] | Reference point |
|---|---|---|
| 0 | -273.15 | Absolute zero |
| 233150 | -40 | Where Celsius and Fahrenheit coincide (−40°) |
| 255372.2222222222 | -17.7777777778 | Zero Fahrenheit (0 °F) |
| 273150 | 0 | Water freezes (0 °C / 32 °F) |
| 273160 | 0.01 | Triple point of water |
| 283150 | 10 | Cool day (10 °C / 50 °F) |
| 293150 | 20 | Room temperature (20 °C / 68 °F) |
| 298150 | 25 | Standard laboratory temperature (25 °C) |
| 303150 | 30 | Hot day (30 °C / 86 °F) |
| 310150 | 37 | Human body temperature (37 °C / 98.6 °F) |
| 313150 | 40 | Heat-wave day (40 °C / 104 °F) |
| 323150 | 50 | Hot tap water (50 °C / 122 °F) |
| 373150 | 100 | Water boils (100 °C / 212 °F) |
| 453150 | 180 | Moderate baking oven (180 °C / 356 °F) |
| 5778000 | 5504.85 | Surface of the Sun (≈5,505 °C) |
Frequently asked questions
What is 1 mK in °C?
How do I convert millikelvins to degrees celsius?
How do I convert degrees celsius back to millikelvins?
At what temperature do the Millikelvin and Celsius scales read the same number?
Can a temperature be below absolute zero?
Popular temperature unit conversions
Convert Millikelvin to other temperature units
Show all Millikelvin conversions
Modern Standard Scales (4 units)
Historical Scales (4 units)
Scientific & Fixed-Point (3 units)
SI Prefixed Kelvin (4 units)
Sources & references
Conversion relationship (°C = (mK × 1/1000) − 273.15) 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.