The F♯ dim7 Chord Explained
F-sharp diminished seventh is a Diminished chord built from the notes F♯, A, C, and E♭. Its root is F♯, and its interval number formula is 1–♭3–♭5–♭♭7. Those intervals are called the root, minor third, diminished fifth, and diminished seventh. You may also see it written as F♯dim7, F♯°7, or plain-text spelling such as F-sharp diminished 7th. If you look at the widget above, you can see and hear how these four notes stack together to create the chord. For a beginner, it can also help to learn how these notes relate by studying chord intervals.
F♯ dim7 Alternate Names
- F♯dim7
- F♯°7
- F-sharp diminished 7th
F♯ dim7 Chord Notes
F♯ dim7 Chord Formula
F♯ dim7 Chord Notation
How To Use F♯ dim7 In Music
Because all the notes are spaced in tight minor-third steps, this chord has a tense, dramatic, and unstable sound that strongly wants to resolve. It often creates suspense, mystery, or urgency, so it appears frequently in classical music, jazz, film music, and transitions between more stable chords. The mood can feel darker or sharper depending on the chords around it: moving from F♯dim7 to G minor can sound like a pull upward, while placing it between gentler chords can make the tension stand out even more. In progressions, it may function as a leading-tone diminished chord, such as vii°7–i, or appear in passing movement like i–#ivo°7–V or I–#i°7–ii. If you want to compare its tense color with a related chord family, see this guide to diminished chords.
F♯ dim7 Chord Inversions
Another useful idea is inversion, which means the chord keeps the same notes but starts on a different one. In root position, F♯ is the lowest note. In 1st inversion, A is lowest, giving A–C–E♭–F♯. In 2nd inversion, C is lowest, giving C–E♭–F♯–A. In 3rd inversion, E♭ is lowest, giving E♭–F♯–A–C. These inversions do not change the chord’s basic identity, but they do change its weight and flow. One inversion may sound smoother moving to the next chord, while another may feel more unsettled or dramatic. Musicians use inversions to create better bass lines, smoother transitions, and different shades of tension without changing the chord itself.
