What is the Boltzmann constant?
The Boltzmann constant is k_B = 1.380649e-23 J/K, exact by SI definition (zero uncertainty). In eV/K it is 8.617333262e-5 eV/K.
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| Value | 1.380649e-23 J/K |
|---|---|
| Symbol | k_B |
| In eV/K | 8.617333262e-5 eV/K |
| Exactness | Exact by SI definition (uncertainty 0) |
| Source | CODATA 2018 |
Frequently asked questions
What is the value of the Boltzmann constant?
k_B = 1.380649e-23 joules per kelvin, an exact defining constant of the SI since 2019.
What does the Boltzmann constant relate?
It links the average kinetic energy of particles to temperature, and connects entropy to microstates via S = k_B·ln(W).
How is k_B related to the gas constant?
R = N_A · k_B, so the molar gas constant equals Avogadro's number times the Boltzmann constant.
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