0 kelvin
0 KTemperature · definition
Celsius and Fahrenheit have shifted zero points. Differences are useful; “twice as hot” in °C or °F is not a physical temperature ratio.
Temperature
Just how hot is 0 kelvin?
Deep cold
0 K
0 kelvin
Celsius and Fahrenheit have shifted zero points.
0 KTemperature
0 K · absolute zero
Absolute zero
Absolute zero is the lowest temperature permitted by thermodynamics, where a system has the least thermal energy available to it.
0 KTemperature
0 K · absolute zero
Celsius and Fahrenheit zero points are offsets. Compare temperature differences, not ratios in °C or °F. The kelvin axis starts at absolute zero.
A little perspective
0 kelvin is the same as absolute zero.
Measurements, assumptions & sources +
0 kelvin
Temperature: 0 K; definition.
Celsius and Fahrenheit have shifted zero points. Differences are useful; “twice as hot” in °C or °F is not a physical temperature ratio.
Absolute zero
Temperature: 0 K; approximate.
The zero of the thermodynamic kelvin scale. It is approached in experiments, not reached by ordinary finite cooling.
NIST — 2022 CODATA fundamental constants
The marked temperature is calibrated. Unmeasured illustration details are representative.
Measurement details
Why these numbers?
Compare 0 kelvin with absolute zero. The notes below explain how each value was chosen.
Absolute zero
0 KTemperature · approximate
The zero of the thermodynamic kelvin scale. It is approached in experiments, not reached by ordinary finite cooling.
- Comparing
- Temperature ↔ Temperature
- Relative size
- We compare temperatures using a difference in kelvins, not a ratio.
How to read the visual
The diagram uses the recorded measurements. Details outside the marked spans do not set the scale.
- Absolute zero: This is an estimate; check the notes for its rounding and uncertainty.
Compare temperature differences in kelvins; Celsius and Fahrenheit ratios are not meaningful.
-273.15 °Cdegrees Celsius
-459.67 °Fdegrees Fahrenheit
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