Measurements of b hadron lifetimes and effective lifetimes at LHCb

Precision measurements of b-hadron lifetimes are a key goal of the LHCb experiment. In the B_s sector, the measurement of the effective lifetimes for B_s mesons decaying to CP-odd, CP-even and flavor specific final states are essential for constraining the B_s mixing parameters, $\Delta \Gamma_s$, the average width, $\Gamma_s$, and the CP-violating phase, $\phi_s$. Measurements of $b$ baryon lifetimes are also important to test theoretical models. We present the latest results from LHCb on these topics.