ConstantID

Boltzmann constant in Hz/K

Physico-chemicalExact

k/h = 2.083 661 912… × 1010 Hz K−1

Value
2.083 661 912… × 1010 Hz K−1
Standard uncertainty
exact
Relative uncertainty
exact
Status
Exact since the 2019 SI redefinition
Symbol
k/h
Source
CODATA 2022 via NIST · NIST entry

NIST prints this exact value cut to 10 digits. ConstantID recomputes it from the defining constants: 2.083 661 912 332 757 298 079 616 618 61 × 1010…

Use in a calculation

# Boltzmann constant in Hz/K, CODATA 2022 (NIST)
boltzmann_constant_in_hz_k = 2.0836619123327572980796166186076373e10  # Hz K^-1, exact

# SciPy: scipy.constants.physical_constants['Boltzmann constant in Hz/K']

What it is

The Boltzmann constant expressed in hertz 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.

Boltzmann constant in Hz/K: CODATA values 1998–2022 relative to the 2022 value, in parts per billion, with one-standard-uncertainty bars−2000−10000+1000+2000parts per billion1998200220062010201420182022

Relative uncertainty

Boltzmann constant in Hz/K: relative standard uncertainty in each CODATA adjustment, logarithmic scale10⁻⁷10⁻⁶10⁻⁵199820022006201020142018exact2022exact
CODATAValue (uncertainty)Relative uncertaintyChange from previous
20222.083 661 912… × 1010exact exact
20182.083 661 912… × 1010exact +0.6 σ of 2014
20142.083 6612(12) × 10105.8 × 10−7 −0.3 σ of 2010
20102.083 6618(19) × 10109.1 × 10−7 −0.7 σ of 2006
20062.083 6644(36) × 10101.7 × 10−6 +0.0 σ of 2002
20022.083 6644(36) × 10101.7 × 10−6 +0.0 σ of 1998
19982.083 6644(36) × 10101.7 × 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).

Related constants

Physico-chemical exact k Boltzmann constant 1.380 649 × 10−23 J K−1 Physico-chemical exact k Boltzmann constant in eV/K 8.617 333 262… × 10−5 eV K−1 Physico-chemical exact k/hc Boltzmann constant in inverse meter per kelvin 69.503 480 04… m−1 K−1