Chord · F# Dominant 9th
F♯9 Chord
F♯9 is F#, A#, C#, E and G# — funky, soulful; James Brown territory.
F♯9 on every instrument
The same 5 notes, 4 sets of hands. Open a diagram for alternate shapes, audio and the mistakes to avoid.
What F♯9 is made of
F# Dominant 9th (F# dominant 9th) is built from the notes F#, A#, C#, E, G#, with the interval pattern 1, 3, 5, b7, 9. A common dominant 9th chord across many styles.
Stack 1, 3, 5, b7 and 9 on a root of F♯ and you get F#, A#, C#, E and G#. That interval recipe is what makes the chord a ninth chord — move the same shape to another root and the character travels with it, which is why C9 sounds like a transposed F♯9.
Dominant 9th: Funky, soulful; James Brown territory.
Spelling: the notes above are written the way a score would write them, not simplified to the nearest piano key. That is why this chord is spelled with F♯ rather than its enharmonic equivalent.
Keys that contain F♯9
All 5 notes sit inside the scale of 4 keys. The roman numeral marks the degree the chord is rooted on.
Other chords on F♯
Same root, different colour.
The same ninth shape, moved
The identical interval recipe, built on other roots.
Questions people ask about F#9
- What notes are in the F#9 chord?
- F#9 is made of F#, A#, C#, E and G# — the 1, 3, 5, b7 and 9 degrees of a ninth chord built on F#.
- What keys use the F#9 chord?
- Every note of F#9 belongs to 4 keys: B Major (V), Cb Major (V), G# Minor (VII), Ab Minor (VII). The roman numeral is the scale degree the chord is rooted on.
- How do you play F#9 on guitar and piano?
- This page shows F#9 on guitar, piano, ukulele and mandolin — 8 voicings in total. Each diagram links to the full instrument page with alternate shapes, audio and common mistakes.
- Is F#9 the same as Gb9?
- Yes. F#9 and Gb9 are enharmonic — identical pitches written two different ways. Which spelling you use depends on the key you are in; F#9 is the spelling this site treats as canonical.
Learn the theory behind it
Why F♯9 behaves the way it does — the guides that explain the chord instead of just spelling it.