Bessel Filter Group Delay Calculator

About this calculator

A Bessel filter is a type of low-pass filter designed to have a maximally flat group delay (also called linear phase response) in its passband, meaning all frequency components of a signal are delayed by nearly the same amount of time and the waveform's shape is preserved with minimal distortion. This calculator estimates that approximately constant delay at DC from the filter's cutoff frequency and order, using the relationship that delay scales roughly as the reciprocal of the cutoff frequency.

Because it preserves pulse shape so well, the Bessel filter is the go-to choice in audio crossover networks, oscilloscope input stages, telecommunications, and pulse/digital circuits where waveform fidelity matters more than a sharp cutoff — unlike Butterworth or Chebyshev filters, which trade phase linearity for steeper roll-off. Analog and RF engineers use group-delay figures like this one to predict how much a filter will smear or shift a signal in time before building it into a circuit.