Boltzmann constant in inverse meter per kelvin
Physico-chemicalExact
= 69.503 480 04… m−1 K−1
- Value
- 69.503 480 04… m−1 K−1
- Standard uncertainty
- exact
- Relative uncertainty
- exact
- Status
- Exact since the 2019 SI redefinition
- Symbol
- Source
- CODATA 2022 via NIST · NIST entry
NIST prints this exact value cut to 10 digits. ConstantID recomputes it from the defining constants: 69.503 480 048 612 740 553 987 406 1344…
Use in a calculation
# Boltzmann constant in inverse meter per kelvin, CODATA 2022 (NIST)
boltzmann_constant_in_inverse_meter_per_ = 6.9503480048612740553987406134401063e1 # m^-1 K^-1, exact
# SciPy: scipy.constants.physical_constants['Boltzmann constant in inverse meter per kelvin']What it is
The Boltzmann constant expressed in inverse metres per kelvin.
It is built only from constants that have exact values since 20 May 2019, so it is exact too; CODATA 2018 was the first adjustment to list it that way.
How the value changed, 1998–2022
Each point is one CODATA adjustment, plotted as its difference from the 2022 value; the bars show one standard uncertainty (an arrowhead means the bar runs off the chart). Diamonds mark adjustments in which the value was exact.
Relative uncertainty
| CODATA | Value (uncertainty) | Relative uncertainty | Change from previous |
|---|---|---|---|
| 2022 | 69.503 480 04… | exact | exact |
| 2018 | 69.503 480 04… | exact | +0.6 σ of 2014 |
| 2014 | 69.503 457(40) | 5.8 × 10−7 | −0.3 σ of 2010 |
| 2010 | 69.503 476(63) | 9.1 × 10−7 | −0.7 σ of 2006 |
| 2006 | 69.503 56(12) | 1.7 × 10−6 | +0.0 σ of 2002 |
| 2002 | 69.503 56(12) | 1.7 × 10−6 | +0.0 σ of 1998 |
| 1998 | 69.503 56(12) | 1.7 × 10−6 |
“Change from previous” is the shift in the value divided by the standard uncertainty of the previous adjustment. Earlier values are converted into the current unit where NIST changed it (for example J s to J Hz⁻¹).