G4
391.995Hz at concert pitch
Press to hear a pure sine tone at this pitch.
MIDI note
67
Piano key
47
Octave
4
Frequency
391.995 Hz
Period
2.5511 ms
Wavelength
0.875 m
Pitch class
G
Notation
SPN
MIDI is the note number synths and software pass around (0–127). Pitch class is the note without its octave — all the Gs share one.
At other reference pitches
| Reference (A4) | G4 frequency | Where you meet it |
|---|---|---|
| 432 Hz | 384.868 Hz | the alternative-tuning circle |
| 440 Hzstandard | 391.995 Hz | the ISO 16 standard — concert pitch |
| 442 Hz | 393.777 Hz | many European orchestras tune a touch sharp |
| 443 Hz | 394.668 Hz | some sharper continental orchestras |
Every row is G4 — only the A4 you tune to changes. A frequency scales straight with the reference: G4 at 432 Hz is the 440 Hz value times 432⁄440.
Move around
Every G
Chords with G in them
G appears in each of these — see the whole chord grid.