Note frequency table (in hertz)
All 88 piano keys in hertz (A4 = 440 Hz). Equal temperament, MIDI numbers. Click a value to hear it.
Quick reference
Essential frequencies for pianists: landmark keys of the range and the A4 reference pitch.
Frequency table
All piano keys from A0 to C8. Rows are chromatic pitch classes, columns are octaves. Click a value to hear the note.
| Note | Sub-contra octave0 | Contra octave1 | Great octave2 | Small octave3 | One-line octave4 | Two-line octave5 | Three-line octave6 | Four-line octave7 | Five-line octave8 |
|---|---|---|---|---|---|---|---|---|---|
| C | |||||||||
| C# | |||||||||
| D | |||||||||
| D# | |||||||||
| E | |||||||||
| F | |||||||||
| F# | |||||||||
| G | |||||||||
| G# | |||||||||
| A | |||||||||
| A# | |||||||||
| B |
How note frequencies are calculated
Every piano key has its own frequency in hertz (Hz) — the number of string vibrations per second. The values are calculated using the equal-temperament formula relative to the A4 reference pitch. The ISO 16 standard fixes A4 = 440 Hz, but other tunings exist too: 432 Hz (a softer, "Baroque" pitch) and 444 Hz (a sharper concert pitch). Each note in the table shows its exact frequency, which you can hear by clicking.
Each octave doubles the frequency: A4 sounds at 440 Hz, A5 at 880 Hz, A3 at 220 Hz. The full range of an 88-key piano spans from A0 (27.50 Hz) to C8 (4186.01 Hz). Knowing frequencies is useful when tuning an instrument, working with audio, and understanding why some notes sound "thicker" and others "thinner".