  The decay rate of the electroweak (EW) vacuum is calculated in the framework
of the standard model (SM) of particle physics, using the recent progresses in
the understanding of the decay rate of metastable vacuum in gauge theories. We
give a manifestly gauge-invariant expression of the decay rate. We also perform
a detailed numerical calculation of the decay rate. With the best-fit values of
the SM parameters, we find that the decay rate of the EW vacuum per unit volume
is about $10^{-577}\ {\rm Gyr^{-1}Gpc^{-3}}$; with the uncertainty in the top
mass, the decay rate is estimated as $10^{-295}-10^{-1465}\ {\rm
Gyr^{-1}Gpc^{-3}}$.
