The Boltzmann constant in eV/K and other units
k and e are both exact since 2019, so k in electronvolts per kelvin is exact: k/e. The table under it gives the thermal energy kT at temperatures people often need.
= 1.380 649 × 10−23 J K−1 about this constant →
| Unit | Value | |
|---|---|---|
| eV/K electronvolts per kelvin | 8.617 333 262 15 × 10−5 | exact |
| meV/K millielectronvolts per kelvin | 0.086 173 332 6215 | exact |
| erg/K ergs per kelvin | 1.380 649 × 10−16 | exact |
| cal/K thermochemical calories per kelvin | 3.299 830 305 93 × 10−24 | exact |
| J/K joules per kelvin | 1.380 649 × 10−23 | exact |
How it is computed: 1.380 649 × 10⁻²³ J/K ÷ 1.602 176 634 × 10⁻¹⁹ J/eV = 8.617 333 262 15 × 10−5.
Thermal energy kT
| Temperature | kT in meV |
|---|---|
| Absolute zero + 1 K | 0.086 1733 |
| Liquid helium (4.2 K) | 0.361 928 |
| Liquid nitrogen (77 K) | 6.635 35 |
| Water freezes (273.15 K) | 23.5382 |
| Room temperature (293.15 K, 20 °C) | 25.2617 |
| Standard 25 °C (298.15 K) | 25.6926 |
| 300 K | 25.852 |
| Body temperature (310.15 K, 37 °C) | 26.7267 |
| Sun's surface (about 5772 K) | 497.392 |
All values computed from the CODATA 2022 value and unit definitions (SI Brochure, NIST SP 811). Exact values are rounded only for display. Checks.
Other conversions
- Speed of light in mph, km/h and other units
- Gravitational constant G in CGS and other units
- Planck constant in eV·s and other units
- Reduced Planck constant ħ in eV·s, MeV·fm and other units
- Gas constant R in L·atm/(mol·K), cal/(mol·K) and other units
- Electron mass in MeV/c², grams and daltons
- Elementary charge in statcoulombs (esu) and other units
- Standard gravity in ft/s², m/s² and other units
- Avogadro constant per pound-mole and other units