G♯0 — 25.957 Hz
G♯0 (G-sharp 0) is 25.957 Hz in standard equal temperament at A=440 Hz. It is MIDI note number 20. This is the sharp spelling of this pitch — see also A♭0.
G♯ is the leading tone in A major and a key-signature accidental in sharp keys from A major onward.
G♯0 Frequency in All Tuning Systems
| Temperament | Frequency (Hz) | Cents from Equal | Common Usage |
|---|---|---|---|
| Equal Temperament | 25.957 Hz | 0.00 | Modern standard; piano, fretted instruments |
| Pythagorean Tuning | 26.104 Hz | +9.78 | Medieval/early music; string ensemble open fifths |
| Just / Pure | 26.163 Hz | +13.69 | A cappella vocal, barbershop, Renaissance |
| Meantone 1/3 Comma | 25.617 Hz | -22.83 | Renaissance vocal music in minor keys |
| Meantone 1/4 Comma | 25.701 Hz | -17.16 | Renaissance keyboard, early Baroque organ |
| 1/6 SC - Attenuated | 25.783 Hz | -11.64 | Baroque orchestral ensemble compromise |
| Kellner's Bach | 26.015 Hz | +3.86 | Bach keyboard reconstruction |
| Kirnberger III | 26.015 Hz | +3.86 | Classical-era keyboard, keys near C major |
| Vallotti | 26.015 Hz | +3.86 | Baroque/Classical orchestral tuning |
| Werckmeister III | 26.015 Hz | +3.86 | Baroque keyboard; Bach contemporaries |
| Werckmeister IV | 25.927 Hz | -2.00 | Baroque keyboard, strong key contrast |
| Werckmeister V | 25.927 Hz | -2.00 | Specialized Baroque keyboard |
Positive cents = sharper than equal temperament. Negative cents = flatter. 100 cents = 1 semitone.
G♯0 at Different Concert Pitches
The same note varies in frequency depending on the concert pitch standard used by your ensemble.
| Concert Pitch | Frequency (Hz) | Common Usage |
|---|---|---|
| A = 440 Hz (ISO standard) | 25.957 Hz | US, UK, and most modern ensembles worldwide |
| A = 442 Hz | 26.075 Hz | Many European orchestras; France, Germany |
| A = 443 Hz | 26.134 Hz | Berlin Philharmonic; some US orchestras |
| A = 432 Hz | 25.485 Hz | Alternative tuning; Baroque revival |
| A = 415 Hz (Baroque) | 24.482 Hz | Historically-informed Baroque performance |
f = f_at_A440 × (concert_pitch / 440)
G♯0 and A♭0 — Enharmonic Equivalents
G♯0 and A♭0 are enharmonic equivalents — they sound identical at 25.957 Hz but are written differently depending on the musical context.
When to Write G♯0
G♯ is the leading tone in A major and a key-signature accidental in sharp keys from A major onward.
Composers write G♯ in sharp-key contexts — as the leading tone of A major, the 3rd of E major, or a chromatic neighbor tone in sharp keys. When a note resolves upward to A, the correct spelling is G♯ (not A♭), because it shows the note's harmonic function as a leading tone.
Major scales containing G♯0: A major (7th / leading tone), E major (3rd), B major (6th), F♯ major (2nd), C♯ major (5th).
Minor scales containing G♯0: C♯ minor (5th), G♯ minor (tonic), F♯ minor (2nd), E minor (3rd, melodic ascending).
G♯0 in Instrument Literature
String players encounter G♯ in A major, one of the most important keys for violin repertoire. The A major scale (with its 3 sharps: F♯, C♯, G♯) is fundamental to string technique. Pianists see G♯ in Beethoven sonatas and other Classical-era works in A and E major.
In fixed-do solfège, G♯ is sung as "si" (♯5). In A major with moveable do, it is "ti" (the leading tone).
How A♭0 Differs in Context
While A♭0 sounds identical to G♯0, it belongs to a different set of keys and carries different harmonic implications.
A♭0: A♭ is the tonic of A♭ major (4 flats) and appears frequently in Romantic-era piano literature and jazz standards.
Major scales: A♭ major (tonic), D♭ major (5th), E♭ major (4th).
Minor scales: F minor (3rd), C minor (6th), B♭ minor (7th).
A♭ is one of the most comfortable keys for B♭ clarinet and trumpet (concert A♭ = written B♭). Horn players in orchestral settings read A♭ regularly. Jazz pianists use A♭ major frequently, and it is a staple key in the Great American Songbook repertoire.
Enharmonic equivalents share the same frequency in equal temperament. In historical temperaments like Pythagorean or meantone, they may differ slightly — see the temperament comparison table above for this note's exact deviations.
Why G♯0 Varies Across Tuning Systems
G♯0 shows a maximum deviation of -22.83 cents in Meantone 1/3 Comma compared to equal temperament. This 23-cent difference is clearly audible to trained musicians and reflects how different tuning philosophies prioritize interval purity over equal distribution.
In Meantone 1/3 Comma, G♯0 is tuned flatter than equal temperament, reflecting this system's approach to distributing the Pythagorean comma across the chromatic scale.
4 of the 15 non-equal temperaments deviate by more than 10 cents for G♯0, making this note one where tuning system choice has a meaningful impact on pitch.
G♯0 Across All Tuning Systems
Explore how G♯0 is tuned in each historical temperament system. Each tuning system gives G♯0 a slightly different frequency, affecting the harmonic character of chords and melodies.
G♯0 in Historical Temperament Systems
Explore how G♯0 (25.957 Hz in equal temperament) is tuned in each of the 15 historical non-equal temperament systems. Each system places G♯0 at a slightly different frequency based on its mathematical basis.
Tune G♯0 with precision — Get Tunable.
Tunable supports 15+ tuning systems including equal temperament, Pythagorean, just intonation, and historical well-temperaments. See exact Hz values in real-time as you play.
