This paper presents an interactive modelling method for synthesizing the components' values of a single-stage band pass filter with an antiparallel configuration and for predicting their electrical characteristics. The filter model is based on approximate but sufficiently accurate closed-form expressions having three independent parameters as arguments, two of which are angular frequencies of transmission zeros in the lower and the upper stopband. The proposed method is implemented within a program for electrical circuit simulation to obtain a bandpass filter model with tuneable frequency characteristics.