TFT

Frequency to Musical Note Converter

Convert any frequency in Hz to its corresponding musical note and octave — and back again. Free online pitch frequency converter for musicians, audio engineers, and music theory students.

Understanding Musical Frequency

Musical notes correspond to specific frequencies measured in Hertz. Higher frequencies produce higher pitches. Lower frequencies produce lower pitches. The standard tuning reference is A4 at 440 Hz.

Each octave doubles the frequency. A4 at 440 Hz becomes A5 at 880 Hz. A3 sits at 220 Hz. This doubling pattern applies to all notes across the musical spectrum.

Note Frequency Chart (Equal Temperament)

NoteOctave 3Octave 4Octave 5Octave 6
C130.81 Hz261.63 Hz523.25 Hz1046.50 Hz
C#/Db138.59 Hz277.18 Hz554.37 Hz1108.73 Hz
D146.83 Hz293.66 Hz587.33 Hz1174.66 Hz
D#/Eb155.56 Hz311.13 Hz622.25 Hz1244.51 Hz
E164.81 Hz329.63 Hz659.25 Hz1318.51 Hz
F174.61 Hz349.23 Hz698.46 Hz1396.91 Hz
F#/Gb185.00 Hz369.99 Hz739.99 Hz1479.98 Hz
G196.00 Hz392.00 Hz783.99 Hz1567.98 Hz
G#/Ab207.65 Hz415.30 Hz830.61 Hz1661.22 Hz
A220.00 Hz440.00 Hz880.00 Hz1760.00 Hz
A#/Bb233.08 Hz466.16 Hz932.33 Hz1864.66 Hz
B246.94 Hz493.88 Hz987.77 Hz1975.53 Hz

Frequency to Note Conversion Formula

Calculate musical note from frequency using equal temperament tuning.

n = 12 × log2(frequency ÷ 440) + 69
note = round(n) - 69 (semitones from A4)
octave = floor((round(n) - 9) ÷ 12)
frequency = 440 × 2^(n/12)

Where n = MIDI note number, A4 = MIDI note 69, frequency in Hz

Example: Finding the note for 523.25 Hz

n = 12 × log2(523.25 ÷ 440) + 69 = 72 MIDI note 72 = C5 (Middle C is C4 at 261.63 Hz)

Standard Tuning References

StandardA4 FrequencyCommon Use
Concert Pitch440 HzInternational standard since 1955
Baroque Pitch415 HzHistorical performance practice
Classical Pitch430 Hz18th-19th century orchestras
Orchestral Pitch442 HzModern European orchestras
High Pitch444 HzSome modern orchestras
Scientific Pitch432 HzAlternative tuning movement

Guitar Standard Tuning Frequencies

  • 6th string (E2): 82.41 Hz
  • 5th string (A2): 110.00 Hz
  • 4th string (D3): 146.83 Hz
  • 3rd string (G3): 196.00 Hz
  • 2nd string (B3): 246.94 Hz
  • 1st string (E4): 329.63 Hz

Frequently Asked Questions

What is the frequency of middle C?

Middle C (C4) vibrates at 261.63 Hz in equal temperament tuning with A4 = 440 Hz. This note sits on the first ledger line below the treble clef staff.

Why is A4 set to 440 Hz?

The International Organization for Standardization adopted 440 Hz as the concert pitch standard in 1955. This unified tuning across orchestras and instrument manufacturers worldwide.

What is the highest note humans can hear?

Young adults can hear up to 20,000 Hz (20 kHz). The highest piano note (C8) reaches 4186 Hz. Hearing range decreases with age, especially for high frequencies.

How do I tune my instrument using frequency?

Use a tuner app or device that displays frequency. Play each string or note and adjust until the displayed frequency matches the target. Fine-tune by listening for beats to disappear.

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