The vacuum permeability or magnetic constant is an ideal physical constant for the value of magnetic permeability in a classical vacuum and equal to $4π10^{-7}$.

Symbol
$\mu_{\mathrm{0}}$
Unit
H/m
Formulae
$1.2566370614359173e-06$
Used in
$c_{\mathrm{SI}}$
$L_{\mathrm{1}}$
$L_{\mathrm{2}}$
$L_{\mathrm{3}}$
$L_{\mathrm{m}}$
$M_{\mathrm{m}}$