G4 at a glance
All values assume twelve-tone equal temperament at the international standard pitch of A4 = 440 Hz. In that system every semitone has the same size - a frequency ratio of 2^(1/12) - so G4 is exactly 440 × 2^(-2/12) Hz. Under alternative references the note shifts with the reference: at A4 = 432 Hz, G4 becomes 384.87 Hz.
G in every octave
| Note | Frequency | MIDI | Piano key |
|---|---|---|---|
| G1 | 49.00 Hz | 31 | 11 |
| G2 | 98.00 Hz | 43 | 23 |
| G3 | 196.00 Hz | 55 | 35 |
| G4 ← | 392.00 Hz | 67 | 47 |
| G5 | 783.99 Hz | 79 | 59 |
| G6 | 1568.0 Hz | 91 | 71 |
| G7 | 3136.0 Hz | 103 | 83 |
Each octave doubles the frequency - the simplest relationship in music, and the reason notes an octave apart sound like “the same note, higher”.
Neighboring notes
One semitone down is F♯4 at 369.99 Hz; one semitone up is G♯4 at 415.30 Hz. Need a frequency between notes, or a different waveform? The tone generator plays anything from 20 Hz to 20 kHz; the note ↔ frequency converter does the math both directions, and the chromatic tuner listens to your instrument and shows the offset in cents.