In the paper approximate calculation algorithm for single phase rectifier with C filter is described. The offered algorithm contains formulas which allow determining capacitor current, total power factor as well as capacitor rated ripple current and equivalent series resistance without referring to datasheet. Although the formulas used in this algorithm are based on simplified mathematical models, there are influential circuit parameters observed such as transformer leakage inductive reactance, diode slope resistance and diode commutation interval. The algorithm corresponds to the analyzer style. It means that there are completely given single phase transformer, diodes, capacitor battery parameters and load resistance, and the analyzer finds out voltages, currents and powers. The algorithm contains only evaluated formulas so there is no need for advanced mathematics operations. It is tested on MS Excel. Calculation in Excel is not fully automated: there are two manually operable cells for leading the iteration process to its convergence