A single-phase single-stage flying inductor based buck-boost inverter (S²FIB²I) is presented in this paper. Operation in buck, boost and buck-boost modes gives the proposed topology the ability to inject power into the grid at a wide range of input voltages. In other words, the proposed inverter has a dynamic voltage gain. The direct connection of the negative terminal of the input source with the neutral terminal of the power grid causes that in photovoltaic applications, the problem of injecting even harmonics into the grid is solved and the leakage current is completely eliminated. The absence of electrolytic capacitors in the proposed converter increases the life and reliability of the system. Also, the ability to operate at nonnity power factor allows the proposed inverter to control the reactive power at its output terminals. Theoretical analysis, design of passive elements and 1 kW simulation results are given to prove the accuracy of the proposed inverter performance.