with filter calculator pro you can calculate the parameters or components of a passive RL, RC, LC, Butterworth, Bessel, Chebyshev, and active filter.

Filter calculator has the following features:
RC filter calculations.
RL filter calculations.
LC filter calculations.
Passive Butterworth filter calculations (2,3,4, and 5 pole Butterworth filter).
Active Butterworth, Bessel, Chebychev filter calculations.
filter calculator is suitable for electronics design and electronics course study

You can choose to calculate the parameters of the filter or calculate the circuit components.