Filter Calculators: Free Passive & Active Circuit Design Tools

Design precision filters for any application with our free online filter calculators. Whether you need a simple RC low-pass for audio anti-aliasing, a sharp Chebyshev bandpass for RF signal selection, or an active Butterworth op-amp filter for instrumentation, these tools calculate exact component values instantly. Enter your cutoff frequency, passband ripple, stopband attenuation, and filter order to receive resistor and capacitor values for passive designs, or R, C, and gain settings for active Sallen-Key and multiple-feedback topologies. Each calculator includes frequency response plots, phase delay data, and group delay characteristics to ensure your filter meets signal integrity requirements. Audio engineers, RF designers, and embedded developers use these tools to eliminate tedious pole-zero calculations and ensure stable, predictable filter performance. From first-order RC networks to eighth-order elliptic filters, our filter calculators cover every frequency-selective design need. No signup required—access from any device and build precise filters with confidence.