Theoretical calculation based on detailed balance and incorporating different realistic optical and electrical losses predicts conversion efficiency beyond 22% for single-junction perovskite devices. In dual-junction perovskite/silicon devices, theoretical conversion efficiency around 40% is been determined. However, dramatic drop in the conversion efficiency is shown to be due to the glass reflection and FTO parasitic absorption losses. Additionally, practical conversion efficiency limits of dual-junction two-terminal perovskite/silicon tandem solar cell of 30% are achievable as reported in this work using state-of-the-art demonstrated devices. Additionally, various crystalline silicon (industry and laboratory demonstrated) technologies are used as the bottom cell for the current matched tandem cell stacks with higher relative improvements when using commercial c-Si solar cells. Moreover, the effect of eliminating the parasitic resistances and enhancing the external radiative efficiency (ERE) in the perovskite junction on tandem performance are also investigated enhancing the stack efficiencies.