Convert Millikelvin to Kelvin
Convert millikelvins to kelvins instantly. 1 mK = 0.001 K — use the live calculator, the exact formula, a reference-temperature table and worked examples. Also check the Kelvin 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.
Kelvin
The kelvin (K) is the SI base unit of thermodynamic temperature, defined by fixing the Boltzmann constant k at exactly 1.380649×10⁻²³ J/K. Zero kelvin is absolute zero, the lowest temperature physically possible, and kelvin values are written without a degree sign.
Named for William Thomson, 1st Baron Kelvin, who in 1848 calculated the value of absolute zero (about −273 °C) and proposed an absolute thermodynamic scale. His title comes from the River Kelvin, which flows past the University of Glasgow in Scotland.
The universal temperature unit of science and engineering — physics, chemistry, astronomy, and materials science — and the standard for color temperature in photography, displays, and lighting (a 5600 K daylight bulb).
Proposed by William Thomson (Lord Kelvin) in 1848; adopted as an SI base unit by the 10th CGPM in 1954 and redefined through the fixed Boltzmann constant by the 26th CGPM, effective May 20, 2019.
Millikelvin to Kelvin conversion formula
The exact relationship between millikelvins and kelvins:
To convert millikelvins to kelvins, multiply the value in millikelvins by 1/1000. To reverse, multiply the value in kelvins by 1000.
Both units count upward from absolute zero, so 0 mK = 0 K and the relationship is a pure ratio.
How to use this converter
Type a value into the calculator. The result in kelvins updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Kelvin to Millikelvin converter for the reverse direction.
Step-by-step: convert millikelvins to kelvins
- Write down the temperature in millikelvins (mK).
- Multiply the value in millikelvins by 1/1000.
- The result is the same temperature expressed in kelvins (K).
- To reverse, multiply the value in kelvins by 1000 — or open the Kelvin to Millikelvin converter.
Worked examples
Example 1 — Convert 1 mK to K:
1 × 1/1000 = 0.001 K
Example 2 — Convert 100 mK to K:
100 × 1/1000 = 0.1 K
Millikelvin to Kelvin conversion table
Physically meaningful reference temperatures, from absolute zero to the surface of the Sun, converted from millikelvins to kelvins:
| Millikelvin [mK] | Kelvin [K] | Reference point |
|---|---|---|
| 0 | 0 | Absolute zero |
| 233150 | 233.15 | Where Celsius and Fahrenheit coincide (−40°) |
| 255372.2222222222 | 255.3722222222 | Zero Fahrenheit (0 °F) |
| 273150 | 273.15 | Water freezes (0 °C / 32 °F) |
| 273160 | 273.16 | Triple point of water |
| 283150 | 283.15 | Cool day (10 °C / 50 °F) |
| 293150 | 293.15 | Room temperature (20 °C / 68 °F) |
| 298150 | 298.15 | Standard laboratory temperature (25 °C) |
| 303150 | 303.15 | Hot day (30 °C / 86 °F) |
| 310150 | 310.15 | Human body temperature (37 °C / 98.6 °F) |
| 313150 | 313.15 | Heat-wave day (40 °C / 104 °F) |
| 323150 | 323.15 | Hot tap water (50 °C / 122 °F) |
| 373150 | 373.15 | Water boils (100 °C / 212 °F) |
| 453150 | 453.15 | Moderate baking oven (180 °C / 356 °F) |
| 5778000 | 5778 | Surface of the Sun (≈5,505 °C) |
Frequently asked questions
How many kelvins is 1 millikelvin?
How do I convert millikelvins to kelvins?
How do I convert kelvins back to millikelvins?
How many kelvins is 100 millikelvins?
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 (1 mK = 0.001 K) 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.