The figure of merit for permanent magnet is the maximum energy product (BH)max in the units of MGOe. Sintered Nd2Fe14B and SmCo magnets show high 64 and 28 MGOe of theoretical (BH)max, respectively. However, low operation temperature of NdFeB, which may lead to loss of machine power, and availability of rare-earth and transition elements are potential barriers to EV motor and other applications. Thus, aiming at developing high temperature magnets without rare-earth and transition elements, we have theoretically calculated the (BH)max for MnBi and t-phase MnAl alloys using density functional theory and modified Skomski’s equation. Our calculations predict 20 MGOe (3.66 ÁB/f.u.; Hk = 53 kOe) and 12.5 MGOe for MnBi and MnAl alloys, respectively. Accordingly, it is envisioned that core-shell MnBi-soft metal and MnAl-soft metal micro/nanoparticles will exhibit large remanent magnetization, thereby increasing the (BH)max to 51 MGOe and 53 MGOe for MnAl and MnBi core-shell nanoparticles, respectively.