Data:CODATA Recommended Values of the Fundamental Physical Constants 2006

Further information: CODATA Recommended Values of the Fundamental Physical Constants

Quantity	Symbol	Value	ur
Speed of light in vacuum	c, c0	299 792 458 m s−1	exact
Magnetic constant	μ0	4π × 10−7 H m−1 ≈ 1.256 637 061… × 10−6 H m−1	exact
Electric constant	ε0 = (μ0c20)−1	8.854 187 816… × 10−12 F m−1	exact
Newtonian constant of gravitation	G	6.674 28(67) × 10−11 N m2 kg−2	1.0 × 10−4
Planck constant	h ħ = h/2π	6.626 068 96(33) × 10−34 J s 1.054 551 628(53) × 10−34 J s	5.0 × 10−8 5.0 × 10−8
Elementary charge	e	1.602 176 487(40) × 10−19 C	2.5 × 10−8
Magnetic flux quantum	Φ0 = h/2e	2.067 833 667(52) × 10−15 Wb	2.5 × 10−8
Conductance quantum	G0 = 2e2/h	7.748 091 7004(53) × 10−5 S	6.8 × 10−10
Electron mass	me	5.485 799 0943(23) × 10−4 u = 9.109 382 15(45) × 10−31 kg	4.2 × 10−10 5.0 × 10−8
Proton mass	mp	1.007 276 466 77(10) u 1.672 621 637(83) × 10−27 kg	1.0 × 10−10 5.0 × 10−8
Proton–electron mass ratio	mp/me	1836.152 672 47(80)	4.3 × 10−10
Fine structure constant	α = μ0c0e2/2h α−1	7.297 352 5376(50) × 10−3 137.035 999 679(94)	6.8 × 10−10 6.8 × 10−10
Rydberg constant	R∞	10 973 731.568 527(73) m−1	6.6 × 10−12
Avogadro constant	NA	6.022 141 79(30) × 1023 mol−1	5.0 × 10−8
Faraday constant	F = NAe	96 485.3399(24) C mol−1	2.5 × 10−8
Molar gas constant	R	8.314 472(15) J K−1 mol−1	1.7 × 10−6
Boltzmann constant	k = R/NA	1.380 6504(24) × 10−23 J K−1	1.7 × 10−6
Stefan–Bolzmann constant	σ = (π2/60)k4/ħ3c20	5.670 400(40) × 10−8 W m−2 K−4	7.0 × 10−6
(Unified) atomic mass unit	u	1.660 538 782(83) × 10−27 kg	5.0 × 10−8

Reference

Mohr, Peter J.; Taylor, Barry N.; Newell, David B. CODATA Recommended Values of the Fundamental Physical Constants: 2006. Rev. Mod. Phys. 2008, 80 (2), 633–730. doi:10.1103/RevModPhys.80.633, <http://physics.nist.gov/cuu/Constants/codata.pdf>.