Equalizer Frequency Calculator

An audio equalizer shapes sound by boosting or cutting specific frequency ranges — the Equalizer Frequency Calculator works out the exact filter boundaries for any EQ band so you can tune precisely without guessing. Enter your center frequency, Q factor, and gain, then select a filter type (Peaking, Low Pass, High Pass, Band Pass, or Notch) and sample rate. You'll get the filter's bandwidth in Hz and octaves, plus the lower and upper -3dB cutoff frequencies and angular frequency. Also try the Lightning Distance Calculator.

Results

Bandwidth

Bandwidth (Octaves)

Lower -3dB Frequency

Upper -3dB Frequency

Angular Frequency

What is Q factor in equalizer design?

Q factor (quality factor) determines the bandwidth of an EQ filter. Higher Q values create narrower, more precise frequency adjustments, while lower Q values affect a broader range of frequencies. Q is calculated as center frequency divided by bandwidth. See also our calculate Speaker Impedance.

How do you calculate the bandwidth of an EQ filter?

Bandwidth is calculated using the formula BW = f0 / Q, where f0 is the center frequency and Q is the quality factor. The bandwidth represents the frequency range between the -3dB points of the filter response.

What's the difference between peaking and bandpass filters?

Peaking filters boost or cut frequencies around a center point while allowing all frequencies to pass through. Bandpass filters only allow frequencies within a specific range to pass, blocking frequencies outside that range.

How does sample rate affect EQ filter calculations?

Sample rate determines the maximum frequency that can be processed (Nyquist frequency = sample rate / 2). Higher sample rates allow for more precise filter calculations at high frequencies and reduce digital artifacts. You might also find our calculate Doppler Effect Observed Frequency (f′) useful.

What is the relationship between Q factor and bandwidth in octaves?

Bandwidth in octaves (N) is approximately equal to 1.44/Q for narrow-band filters. This relationship helps audio engineers translate between different measurement systems when designing EQ curves.

How do I choose the right Q factor for my EQ?

For musical applications, Q values between 0.5-2.0 sound natural. Higher Q values (3-10+) are useful for surgical cuts or correcting specific resonances. Lower Q values (0.3-0.7) work well for gentle tonal shaping.

What are the -3dB cutoff frequencies?

The -3dB cutoff frequencies are the points where the filter response drops to half power (70.7% of the peak level). These frequencies define the effective bandwidth of the filter and are used to calculate Q factor.