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Hz to Note
Equal-temperament frequency → note lookup with cents offset.
440 Hz, A4
Note
A
Octave
4
Cents offset
0
Equal temperament · A4 = 440 Hz · Play this frequency in the tone generator
Frequency to note math
Musical pitch uses logarithmic spacing: each octave doubles frequency. Equal temperament divides the octave into 12 semitones of 100 cents each, anchored so A4 = 440 Hz.
Reading cents
Cents measure deviation from the nearest note. +50 cents is halfway to the next semitone sharp; −50 cents is halfway flat. Tuners aim for ±5 cents or less.
Common references
440 Hz = A4 concert pitch. 261.63 Hz ≈ C4 middle C. Use our fixed Hz pages or Tone Generator to hear any converted frequency.
How to use
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Use sliders and controls to set frequency, volume, and waveform. Changes apply in real time.
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Frequently asked questions
What tuning system is used?
Equal temperament with A4 = 440 Hz.