The article is devoted to a suitable choice of input parameters for the efficient running of a self-developed code used for damage detection. The code was prepared in Office Excel VBA, which used a non-destructive vibration-based method. The primary aim of the code is to determine the change in bending stiffness by using the FE model updating method, and the aim of the paper is to determine the effect of the input data on the bending stiffness calculations. The code was applied for a numerical model of a steel bar. The steel bar was a simply supported beam with a span of 3.5 m. The time of the calculations and precision of the identification were investigated. The values of the time consumption depend on the input values, the desired limit of the accepted error, and the length of the step in every iteration. Data from an experimental model was analysed. The model was made of wooden and plaster boards. The calculations were done in accordance with suitable input data from a parametric study.