# Template:Physconst

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This template provides easy inclusion of recent values of physical constants in articles. Presently, it returns CODATA 2014 recommended values, but the template will be updated when more recent values become available; in particular, when the proposed redefinition of SI base units is approved and takes effect, the values of several constants will become exact (e.g. e), whereas some previously exactly defined constants will acquire an uncertainty (e.g. μ0).

## Contents

### Usage

#### Arguments

`symbol`
If set to `yes`, the value is preceded by the symbol of the constant, followed by or = depending on whether or not `round` is set.
`round`
If omitted, the value is shown along with its standard uncertainty. If set to an integer n, the value is rounded to the first n digits after the decimal point (retaining trailing zeros). If set to `auto`, the value is rounded to the most digits such that the standard uncertainty is no more than 0.5 units in the last place.
`unit`
If set to `no`, the unit of measurement is not shown.
`ref`
If set to `no`, no reference is given. If set to `only`, only the reference is given.
`after`
Text (e.g. punctuation) to be shown after the constant before the reference.
`runc`
If set to `yes`, this will provide only the relative standard uncertainty of the value and its reference.

#### Available constants

Code Constant Value "auto" rounding Relative standard uncertainty
alpha fine-structure constant α = 7.2973525664(17)×10−3 α ≈ 7.297352566×10−3 ur(α) = 2.3×10−10[1]
bwien Wien's displacement constant b = 2.8977729(17)×10−3 m⋅K b ≈ 2.897773×10−3 m⋅K ur(b) = 5.7×10−7[2]
c speed of light c = 299792458 m/s c ≈ 299792458 m/s ur(c) = 0[3]
e elementary charge e = 1.6021766208(98)×10−19 C e ≈ 1.60217662×10−19 C ur(e) = 6.1×10−9[4]
eps0 vacuum permittivity ε0 = 8.854187817...×10−12 F⋅m−1 ε0 ≈ 8.854187817×10−12 F⋅m−1 ur(ε0) = 0[5]
eV electronvolt 1 eV = 1.6021766208(98)×10−19 J 1 eV ≈ 1.60217662×10−19 J ur(1 eV) = 6.1×10−9[6]
F Faraday constant F = 96485.33289(59) C⋅mol−1 F ≈ 96485.333 C⋅mol−1 ur(F) = 6.2×10−9[7]
G gravitational constant G = 6.67408(31)×10−11 m3⋅kg−1⋅s−2 G ≈ 6.674×10−11 m3⋅kg−1⋅s−2 ur(G) = 4.7×10−5[8]
G0 conductance quantum G0 = 7.7480917310(18)×10−5 S G0 ≈ 7.748091731×10−5 S ur(G0) = 2.3×10−10[9]
ge electron g-factor ge = −2.00231930436182(52) ge ≈ −2.002319304362 ur(ge) = 2.6×10−13[10]
gmu muon g-factor gμ = −2.0023318418(13) gμ ≈ −2.002331842 ur(gμ) = 6.3×10−10[11]
h Planck constant h = 6.626070040(81)×10−34 J⋅s h ≈ 6.626070×10−34 J⋅s ur(h) = 1.2×10−8[12]
hbar Planck constant ħ = 1.054571800(13)×10−34 J⋅s ħ ≈ 1.0545718×10−34 J⋅s ur(ħ) = 1.2×10−8[13]
invalpha inverse fine-structure constant 1/α = 137.035999139(31) 1/α ≈ 137.03599914 ur(1/α) = 2.3×10−10[14]
k Boltzmann constant k = 1.38064852(79)×10−23 J⋅K−1 k ≈ 1.3806485×10−23 J⋅K−1 ur(k) = 5.7×10−7[15]
KJ Josephson constant KJ = 483597.8525(30)×109 Hz⋅V−1 KJ ≈ 483597.853×109 Hz⋅V−1 ur(KJ) = 6.1×10−9[16]
lP Planck length lP = 1.616229(38)×10−35 m lP ≈ 1.6162×10−35 m ur(lP) = 2.3×10−5[17]
me electron mass me = 9.10938356(11)×10−31 kg me ≈ 9.1093836×10−31 kg ur(me) = 1.2×10−8[18]
mmu muon mass mμ = 1.883531594(48)×10−28 kg mμ ≈ 1.8835316×10−28 kg ur(mμ) = 2.5×10−8[19]
mP Planck mass mP = 2.176470(51)×10−8 kg mP ≈ 2.1765×10−8 kg ur(mP) = 2.3×10−5[20]
mp proton mass mp = 1.672621898(21)×10−27 kg mp ≈ 1.6726219×10−27 kg ur(mp) = 1.2×10−8[21]
mpome proton-to-electron mass ratio mp/me = 1836.15267389(17) mp/me ≈ 1836.1526739 ur(mp/me) = 9.5×10−11[22]
mtau tau mass mτ = 3.16747(29)×10−27 kg mτ ≈ 3.1675×10−27 kg ur(mτ) = 9.0×10−5[23]
mu atomic mass constant mu = 1.660539040(20)×10−27 kg mu ≈ 1.66053904×10−27 kg ur(mu) = 1.2×10−8[24]
mu0 vacuum permeability μ0 = 12.566370614...×10−7 N⋅A−2 μ0 ≈ 12.566370614×10−7 N⋅A−2 ur(μ0) = 0[25]
NA Avogadro constant NA = 6.022140857(74)×1023 mol−1 NA ≈ 6.02214086×1023 mol−1 ur(NA) = 1.2×10−8[26]
Phi0 magnetic flux quantum Φ0 = 2.067833831(13)×10−15 Wb Φ0 ≈ 2.06783383×10−15 Wb ur(Φ0) = 6.1×10−9[27]
R gas constant R = 8.3144598(48) J⋅mol−1⋅K−1 R ≈ 8.31446 J⋅mol−1⋅K−1 ur(R) = 5.7×10−7[28]
Rinf Rydberg constant R = 10973731.568508(65) m−1 R ≈ 10973731.5685 m−1 ur(R) = 5.9×10−12[29]
RK von Klitzing constant RK = 25812.8074555(59) Ω RK ≈ 25812.807456 Ω ur(RK) = 2.3×10−10[30]
sigma Stefan–Boltzmann constant σ = 5.670367(13)×10−8 W⋅m−2⋅K−4 σ ≈ 5.67037×10−8 W⋅m−2⋅K−4 ur(σ) = 2.3×10−6[31]
TP Planck temperature TP = 1.416808(33)×1032 K TP ≈ 1.4168×1032 K ur(TP) = 2.3×10−5[32]
tP Planck time tP = 5.39116(13)×10−44 s tP ≈ 5.3912×10−44 s ur(tP) = 2.3×10−5[33]
Z0 characteristic impedance of vacuum Z0 = 376.730313461... Ω Z0 ≈ 376.730313461 Ω ur(Z0) = 0[34]

#### Examples

`{{physconst|c|unit=no|after=&nbsp;[[metre per second|metres per second]].}}`
299792458 metres per second.[3]
`{{physconst|mu0|symbol=yes}}`
μ0 = 12.566370614...×10−7 N⋅A−2[25]
`{{physconst|G|symbol=yes}}`
G = 6.67408(31)×10−11 m3⋅kg−1⋅s−2[8]
`{{physconst|h|round=auto|ref=no}}`
6.626070×10−34 J⋅s
`{{physconst|hbar|round=2|symbol=yes}}`
ħ ≈ 1.05×10−34 J⋅s[13]
`The relative standard uncertainty of ''m''<sub>u</sub> is {{physconst|mu|runc=yes|after=.}}`
The relative standard uncertainty of mu is 1.2×10−8.[24]
`For the electron mass, {{physconst|me|runc=yes|symbol=yes|ref=no}}.`
For the electron mass, ur(me) = 1.2×10−8.
`NIST publishes the CODATA value of the [[elementary charge]].{{physconst|e|ref=only}}`
NIST publishes the CODATA value of the elementary charge.[4]

{{CODATA2010}}

### References

1. ^ "CODATA Value: fine-structure constant". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
2. ^ "CODATA Value: Wien wavelength displacement law constant". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
3. ^ a b "CODATA Value: speed of light in vacuum". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
4. ^ a b "CODATA Value: elementary charge". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-22. 2014 CODATA recommended values
5. ^ "CODATA Value: electric constant". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
6. ^ "CODATA Value: electron volt". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-22. 2014 CODATA recommended values
7. ^ "CODATA Value: Faraday constant". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
8. ^ a b "CODATA Value: Newtonian constant of gravitation". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
9. ^ "CODATA Value: conductance quantum". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
10. ^ "CODATA Value: electron g factor". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
11. ^ "CODATA Value: muon g factor". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
12. ^ "CODATA Value: Planck constant". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
13. ^ a b "CODATA Value: Planck constant over 2 pi". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
14. ^ "CODATA Value: inverse fine-structure constant". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
15. ^ "CODATA Value: Boltzmann constant". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
16. ^ "CODATA Value: Josephson constant". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
17. ^ "CODATA Value: Planck length". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2017-06-22. 2014 CODATA recommended values
18. ^ "CODATA Value: electron mass". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
19. ^ "CODATA Value: muon mass". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
20. ^ "CODATA Value: Planck mass". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2017-06-22. 2014 CODATA recommended values
21. ^ "CODATA Value: proton mass". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
22. ^ "CODATA Value: proton-electron mass ratio". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
23. ^ "CODATA Value: tau mass". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
24. ^ a b "CODATA Value: atomic mass constant". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
25. ^ a b "CODATA Value: magnetic constant". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
26. ^ "CODATA Value: Avogadro constant". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
27. ^ "CODATA Value: magnetic flux quantum". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
28. ^ "CODATA Value: molar gas constant". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
29. ^ "CODATA Value: Rydberg constant". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
30. ^ "CODATA Value: von Klitzing constant". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2017-01-18. 2014 CODATA recommended values
31. ^ "CODATA Value: Stefan-Boltzmann constant". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2015-09-25. 2014 CODATA recommended values
32. ^ "CODATA Value: Planck temperature". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2017-06-22. 2014 CODATA recommended values
33. ^ "CODATA Value: Planck time". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2017-06-22. 2014 CODATA recommended values
34. ^ "CODATA Value: characteristic impedance of vacuum". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2015. Retrieved 2017-01-18. 2014 CODATA recommended values