Abstract In this paper we present results of numerical simulations for the determination of 2D current distributions from magnetic field measurements using a previously developed algorithm. The currents were generated experimentally in the thin layer of a solar cell (the emitter) under light or laser illumination. The three components of the induced magnetic field above the surface of the sample have been measured by sensitive magnetic field detectors. The B Z component, normal to the solar cell surface, was measured by a SQUID with the previously developed CASQ (Current Analysis by SQUID) method. Both the B X and B Y components parallel to the solar cell surface were measured by an inductive coil system under pulsed illumination. Under the approximation of a 2D quasi-static current distribution the solution of the inverse problem of current extraction from measured magnetic field data can be directly obtained by applying the spectral method of Fourier transformation (FT). The errors of the procedure resulting from the limited and discrete set of data points (spatial resolution) are investigated and discussed. The goal of the present investigation is to localize leakage currents in the pn-junction (shunts) and damaged areas in the contact and emitter region of solar cells. Therefore, the FT method was applied to measurements of solar cells damaged by artificial scratches and commercial cells. The results show that such defects can be determined from the current density distributions with the present experimental system and numerical algorithm.