G♯0 / A♭0
25.957Hz at concert pitch
Press to hear a pure sine tone at this pitch.
MIDI note
20
Piano key
—
Octave
0
Frequency
25.957 Hz
Period
38.5253 ms
Wavelength
13.2142 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 G♯s share one. Enharmonic spellings (G♯0 and A♭0) name the same pitch two ways. This note falls outside the 88-key piano, so it has no piano key number.
At other reference pitches
| Reference (A4) | G♯0 frequency | Where you meet it |
|---|---|---|
| 432 Hz | 25.485 Hz | the alternative-tuning circle |
| 440 Hzstandard | 25.957 Hz | the ISO 16 standard — concert pitch |
| 442 Hz | 26.075 Hz | many European orchestras tune a touch sharp |
| 443 Hz | 26.134 Hz | some sharper continental orchestras |
Every row is G♯0 — only the A4 you tune to changes. A frequency scales straight with the reference: G♯0 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.