In this paper, the data, calculation algorithms, and applicability of some traditional magnitudes (M_L, m_b, m_B, M_S, and M_JMA) were first described and compared. Additionally, the theoretical basis and calculation methods of two modern magnitude scales (M_e and M_W) were systematically explored. The determination methods of some moment magnitudes (i.e., M_WW, M_WC, M_Wb, M_wp, and M_dt) were then introduced in accordance with different use data and applicable scenarios. Meanwhile, high-frequency GPS-based observation was increasingly used for the rapid determination of earthquake magnitudes due to the wide availability of GPS observation data. Finally, the time efficiencies of these magnitude determination methods were compared and analyzed, and the applicable scenarios and stability of different magnitude scales were discussed.