add passband add stopband
from to gain ripple/att. act. rpl
sampling freq. 
desired #taps 
actual #taps 

I am working on TFilter2. Screenshot here. Features include CIC (Sinc) filters, effect of quantization, save/load/share, aliasing visualization, and signal chain.

If you want to advertise here, contact me at .

TFilter is being used by many tech companies and universities.

The free online FIR filter design tool

TFilter is a web application that generates linear phase, optimal, equiripple finite impulse response digital filters. It uses a pure javascript implementation of the Parks-McClellan filter design algorithm.


  1. Set the sampling frequency and the desired number of taps.
  2. Specify the passbands (gain > 0) and stopbands (gain = 0). Make sure they don't overlap.
  3. Click the DESIGN FILTER button.

An example configuration is set up for you. To try it, just click the DESIGN FILTER button.

Terms of Usage

The author disclaims all possibly disclaimable liabilities related to TFilter. There is no warranty for anything either.