$|V_{us}|$ is computed using the exclusive $\tau$ lepton branching fractions ${\cal B}(\tau^- \to K^-\nu_\tau)$ and ${\cal B}(\tau^- \to \pi^-\nu_\tau)$ and using the inclusive $\tau$ branching fraction to all ``strange'' final states, ${\cal B}(\tau^- \to X_s^- \nu_\tau)$, computed as the sum of all the relevant exclusive branching fractions. Assuming the Standard Model, the kaon branching fractions measurements ${\cal B}(K^+ \to \ell^+\nu_\ell)$ and ${\cal B}(K^+ \to
\ell^+\pi^0\nu_\ell)$ with $\ell=e,\mu$ are used to improve the experimental determination of ${\cal B}(\tau^- \to X_s^- \nu_\tau)$ and \Vus.