k · Boltzmann constant

볼츠만 상수

Takeaway

The relative standard uncertainty fell by a factor of about 75 from the 1969 to the 2014 edition (4.3×10⁻⁵ → 5.7×10⁻⁷): the error bars narrowed that much.
All 8 earlier editions with a measured value contain the 2022 value within ±1σ (the error bar). The 2022 value is exact.
The largest move between editions came in 1986→1998, at 0.6 times the combined standard uncertainty of the two editions (|z| = 0.6).
Exact from the 2018 edition (fixed by definition rather than measured), so its uncertainty is zero.

Value ±1σ by edition2022

Relative deviation from the 2022 value (symmetric-log axis). Open circles: the error bar does not reach the 2022 value. Squares: exact.

Editionyear of the recommended values (data cut-off)	As printedexactly as in the source table; digits in parentheses are the standard uncertainty in the last digits	Standard uncertaintyhalf-width of the error bar (±1σ)	Relative standard uncertaintystandard uncertainty ÷ \|value\|: bar width relative to the value	Exactfixed by definition, uncertainty zero	z vs previous editionmove from the previous edition ÷ combined standard uncertainty of the two	z vs 2022(2022 value − this value) ÷ this edition's standard uncertainty	Source locationpage and table of the paper, or file and line of NIST's table
1969	1.380622(59) e-23	5.9×10⁻²⁸	4.3×10⁻⁵			0.4576	478 table XXXII
1973	1.380662(44) e-23	4.4×10⁻²⁸	3.2×10⁻⁵		0.5435	−0.2955	719 table 33.1
1986	1.380658(12) e-23	1.2×10⁻²⁸	8.7×10⁻⁶		−0.0877	−0.7500	codata86 p.11 table 2
1998	1.380 6503(24) e-23	2.4×10⁻²⁹	1.7×10⁻⁶		−0.6292	−0.5417	1998 ASCII:58
2002	1.380 6505(24) e-23	2.4×10⁻²⁹	1.7×10⁻⁶		0.0589	−0.6250	2002 ASCII:58
2006	1.380 6504(24) e-23	2.4×10⁻²⁹	1.7×10⁻⁶		−0.0295	−0.5833	2006 ASCII:58
2010	1.380 6488 e-23	1.3×10⁻²⁹	9.4×10⁻⁷		−0.5862	0.1538	2010 ASCII:60
2014	1.380 648 52 e-23	7.9×10⁻³⁰	5.7×10⁻⁷		−0.1841	0.6076	2014 ASCII:60
2018	1.380 649 e-23			yes			2018 ASCII:61
2022	1.380 649 e-23			yes			2022 ASCII:62