Abstract: Herein, we addressed the feasibility of transforming the leakage-rate, measured with He/N₂, Xe/N₂ and SF₆/N₂ tracer gas mixtureand evaluated ingas chromatography analysis, intoheliumstandard leakage-rate. The impact of the gas flow patterns on the transformation accuracy was investigated. The results show that the flow patterns significantly affect the transformation precision. For example, in viscous and molecular flows, the transformation is feasible by calibrating the gas properties, including the viscosity, pressure, temperature and molecular mass; but the problem isthat He-molecule might be too small to be in viscous or molecular flows. The transformation method, developed for the viscous and molecular flows, may serve to roughly estimate the range of He standard leakage-rate in transition flow of the gasmixture through the leaks. In molecular flow, each gas component has a sharply different leakage-rate, though their leakage-rates are the same in viscous flow.