Note frequency chart
The pitch of every note in hertz, tuned to A4 = 440 Hz (equal temperament). Each octave doubles the frequency. Click a note to hear it.
| Note | Octave 2 | Octave 3 | Octave 4 | Octave 5 | Octave 6 | Octave 7 |
|---|---|---|---|---|---|---|
| C / Do | ||||||
| C# / Do# | ||||||
| D / Re | ||||||
| D# / Re# | ||||||
| E / Mi | ||||||
| F / Fa | ||||||
| F# / Fa# | ||||||
| G / Sol | ||||||
| G# / Sol# | ||||||
| A / La | ||||||
| A# / La# | ||||||
| B / Si |
About note frequencies
The frequency of a note is the number of vibrations per second of its sound wave. The higher the frequency, the higher the pitch. Middle C (C4) is 261.63 Hz and the A above it (A4) is the 440 Hz tuning reference.
- What frequency is middle C?
- Middle C (C4) is 261.63 Hz in standard tuning.
- What is A440?
- A440 is the standard tuning reference: the A above middle C (A4) vibrates at 440 Hz. Every other note is derived from it.
- How is the frequency of a note calculated?
- In equal temperament, f = 440 × 2^((n − 69) / 12), where n is the MIDI note number (A4 = 69). Each semitone multiplies the frequency by about 1.0595, and each octave doubles it.