In order to improve the solar cell efficiency of the solar cell concept of interest most efficiently, it is essential to analyze its loss mechanisms. Numerical simulations are used to calculate the individual solar cell loss mechanisms. The calculated current losses can be used to identify the main losses and can give recommendation for the next improvement steps. We present a method for a current density loss analysis of crystalline silicon solar cells based on 2-D and 3-D numerical simulations. With the presented method, a collection of relevant crystalline silicon solar cell concepts are investigated. By determining the main loss mechanisms of each cell concept, the limitations and the potential of the different concepts are pointed out.