Planck temperature
The Planck temperature is a theoretical temperature scale at which quantum gravitational effects are expected to become important.
How big is it?
1.417 × 10³² K · temperature
Temperature · theoretical
A little perspective
Planck temperature vs Fusion plasma: temperature comparison
The Planck temperature is 1.417 × 10³² K higher than the temperature of fusion plasma.
The Planck temperature is a theoretical temperature scale at which quantum gravitational effects are expected to become important.
Fusion plasma is a state of matter where atomic nuclei and electrons are separated and nuclei can undergo nuclear fusion.
Measurements, assumptions & sources +
Planck temperature
Temperature: 1.417 × 10³² K; theoretical.
A theoretical temperature scale where quantum gravity is expected to matter. Current physics does not establish it as an unqualified hottest possible temperature.
NIST — 2022 CODATA fundamental constants
The marked temperature is calibrated. Unmeasured illustration details are representative.
Fusion plasma
Temperature: 100,000,000 K; defined reference.
A 100 million K plasma example. High temperature alone does not specify total thermal energy.
Defined examples — our methodology
The marked temperature is calibrated. Unmeasured illustration details are representative.
Use the visual comparison to explore its scale, then check the measurements and sources.
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Why this measurement?
Why we use 1.417 × 10³² K
We compare the Planck temperature. This is a theoretical value calculated under stated physical assumptions, not a direct observation.
A theoretical temperature scale where quantum gravity is expected to matter. Current physics does not establish it as an unqualified hottest possible temperature.
The picture identifies the subject; the diagram compares the recorded values. How calibrated comparisons work →
Recorded properties
Dimensions and measurements
| Property | Selected value | Recorded range | Basis |
|---|---|---|---|
| 1.417 × 10³² K | Not recorded | theoretical |
Around this scale
Explore nearby values.
Compare examples with lower, similar and higher values. Each card names the measurement being compared.
Sources and method
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The source records and measurement method remain available for inspection.
- NIST — 2022 CODATA fundamental constantsRecommended constants with uncertainties; exact SI definitions are distinguished from measured constants.
There’s always another scale
Follow your curiosity.
Fundamental physicsPlanck length1.616 × 10⁻³⁵ mThe Planck length is a scale formed from fundamental physical constants.
MicroscopicHydrogen atom105.8 pmA hydrogen atom is the simplest neutral atom, with one proton in its nucleus and one electron around it.
MicroscopicDNA double helix2 nmDNA is the molecule that stores hereditary information in living organisms.
TemperatureFusion plasma100,000,000 KFusion plasma is a state of matter where atomic nuclei and electrons are separated and nuclei can undergo nuclear fusion.TemperatureNeutron star surface1,000,000 KNeutron star surface temperature is the intense heat found at the outer layer of a young neutron star after a supernova.
SpaceSun1,391,000 kmThe Sun is the star at the centre of the Solar System.TemperatureSpace Shuttle re-entry plasma8,000 KSpace Shuttle re-entry plasma is the extremely hot, ionised gas layer that forms around a spacecraft as it re-enters Earth's atmosphere at high speed.TemperatureMolten iron1,811 KMolten iron is iron in its liquid state, formed by heating solid iron above its melting point.