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EQ Frequency Calculator

Calculate EQ center frequency, bandwidth, and Q factor for parametric equalizer settings. Octave and semitone spacing for mixing.

Use this result well

Inputs that matter
Center Frequency, Q Factor
Output to expect
EQ Bandwidth Calculator
  • Check the units and required inputs before comparing results.
  • Keep the assumptions with a copied result so you can reproduce the calculation later.
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Sound Design

Reference & details

How it works

Q Factor Definition

Q determines filter narrowness. High Q = narrow notch or peak. Low Q = broad shelving or gentle peak.

Q = Center frequency (f) ÷ Bandwidth (BW)

Bandwidth from Q

Bandwidth in Hz at −3 dB points for peaking filters. Q of 2 at 1000 Hz = 500 Hz bandwidth.

BW = f ÷ Q

Octaves to Q

1 octave bandwidth ≈ Q 1.41. 1/3 octave ≈ Q 4.3. 2 octaves ≈ Q 0.71. Useful for translating graphic EQ to parametric.

Q ≈ 1.41 ÷ Octaves (for moderate Q)

Updated: July 2026

Example Scenarios

Room resonance at 80 Hz — set parametric cut: center 80 Hz, Q 4 (20 Hz bandwidth) for surgical 6 dB cut without affecting adjacent frequencies.

Boost at 4 kHz with Q 1.5 (2.67 kHz bandwidth) — broad enough for natural presence without nasal honk.

31-band 1/3-octave graphic EQ slider at 1 kHz ≈ Q 4.3, bandwidth 233 Hz — replicate with parametric EQ settings.

FAQ

Quality factor — ratio of center frequency to bandwidth. Q=1 is moderate width. Q=10 is very narrow (surgical). Q=0.5 is very broad (gentle shelf-like peak).

Use Q 3–8 for narrow notches targeting specific room modes. Measure with RTA first, then cut exact frequency with narrow Q.

Q 0.7–2.0 for musical boosts and cuts. Broad enough to sound natural, narrow enough for targeted adjustment.

Approximately Q = 1.41 / octaves (at −3dB points). Third-octave (0.33 oct) ≈ Q 4.3. Full octave ≈ Q 1.41.

Shelving filters use slope (dB/octave) rather than Q. Peaking/bell filters use Q. High-pass/low-pass use slope in dB/octave or filter order.

About EQ Frequency Calculator

Parametric EQ settings require understanding the relationship between center frequency, Q factor, and bandwidth. Enter any two values to calculate the third, and convert between octave bandwidth, semitones, and Q for precise equalizer adjustment.