A method of calculating wear volume is developed using the signal processing technique. The lowpass filter with Fourier transform and the “windowing” are implemented in the method. User-defining feature is also included in determining the cutoff frequency of the low-pass filter and the baseline for the volume integration. Commercial software, MatLab, is used for the programming. Since the method uses the original wear data without simplifying the wear shape, it can give a further accurate result than the previously utilized methods, which often adopted the simplification. It becomes further powerful if the contacting body has a general shape rather than that gives well-formed surface traction (e.g., the Hertzian). The validation of applying the average surface roughness, Ra, to the “windowing” and the baseline for volume integration is discussed.