It lies a chromatic semitone above G and a diatonic semitone below A, thus being enharmonic to La Bémol or A♭ (A flat). However, in some temperaments, it is not the same as A-flat. A-flat is a perfect fifth below E-flat, whereas G sharp is a major third above E. Thus A is slightly lower in pitch.
When calculated in equal temperament with a reference of A above middle C as 440 Hz, the frequency of the G♯ semitone is approximately 415.305 Hz. See pitch (music) for a discussion of historical variations in frequency.
G# / A is the only note to have only 1 other enharmonic.