sFilter is a productivity utility for electrical filter design. sFilter enables the user to quickly define a passive filter based on common parameters such as the number of poles, bandwidth, etc. It supports Butterworth (maximally flat passband), Chebyshev Type 1 (user selected passband ripple), Chebyshev Type 2 (inverse Chebyshev or maximally flat passband with user selected stopband ripple), and Bessel (flat group delay) filters in lowpass, highpass, bandpass, and bandstop configurations. In addition, it supports shunt (pi configuration) or series (T configuration) start as well as user selected system impedances. The application illustrates performance with a low pass prototype plot and an annotated schematic, both of which can be printed.