# F♯ Half Diminished 7th piano chord (F♯m7♭5)

F♯m7♭5 contains F♯, A, C and E. A diminished triad with the minor seventh added on top. F♯ is a black key; A, C and E are white.

- Canonical page: https://piano.org/chords/half-diminished/f-sharp/
- Entity: chord:half-diminished-7th:f-sharp
- Notes: F♯ A C E
- Formula: 1 ♭3 ♭5 ♭7
- Intervals from root: P1, m3, TT, m7
- Interval stack (semitones): 3 3 4
- Also written: F♯m7♭5, F#m7b5, F♯ half diminished 7th
- Parameters: A440, 12-TET, 165 mm octave, spans centre to centre

## Construction

| Degree | Note | Interval from root | Semitones |
| --- | --- | --- | --- |
| 1 | F♯ | Perfect unison | 0 |
| ♭3 | A | Minor third | 3 |
| ♭5 | C | Tritone | 6 |
| ♭7 | E | Minor seventh | 10 |

## Fingering

Rest your right hand over the notes with finger 2 on F♯, finger 3 on A, finger 4 on C, finger 5 on E. The left hand mirrors it.
Right hand 2-3-4-5, left hand 5-4-3-2. Source: piano.org fingering method v1.

## Inversions

| Position | Bass | Notes in order | Figured bass | Span |
| --- | --- | --- | --- | --- |
| Root position | F♯ | F♯3 A3 C4 E4 | 7 | 10 st, 138 mm |
| First inversion (F♯m7♭5/A) | A | A3 C4 E4 F♯4 | 6/5 | 9 st, 124 mm |
| Second inversion (F♯m7♭5/C) | C | C4 E4 F♯4 A4 | 4/3 | 9 st, 124 mm |
| Third inversion (F♯m7♭5/E) | E | E4 F♯4 A4 C5 | 4/2 | 8 st, 110 mm |

## Voicings (10)

| Voicing | Notes | Span | Relation | Omits or adds |
| --- | --- | --- | --- | --- |
| Close, root position | F♯3 A3 C4 E4 | 10 st, 138 mm | identical | none |
| Close, first inversion | A3 C4 E4 F♯4 | 9 st, 124 mm | identical | none |
| Close, second inversion | C4 E4 F♯4 A4 | 9 st, 124 mm | identical | none |
| Close, third inversion | E4 F♯4 A4 C5 | 8 st, 110 mm | identical | none |
| Drop 2 | C3 F♯3 A3 E4 | 16 st, 220 mm | identical | none |
| Drop 3 | A2 F♯3 C4 E4 | 19 st, 261 mm | identical | none |
| Drop 2 and 4 | F♯2 C3 A3 E4 | 22 st, 303 mm | identical | none |
| Shell, root ♭7 ♭3 | F♯2 E3 A3 | 15 st, 206 mm | subset | omits C |
| Guide tones, ♭3 and ♭7 | A3 E4 | 7 st, 96 mm | subset | omits F♯ and C |
| Rootless close | A3 C4 E4 | 7 st, 96 mm | subset | omits F♯ |

## Diatonic function by key

| Key | Roman numeral | Function |
| --- | --- | --- |
| E minor | iim7♭5 | Predominant |
| G major | viim7♭5 | Dominant function |

Classification system: common-practice functional harmony.

## Progressions (2)

| Progression | Key | Role | Sequence | Voice leading |
| --- | --- | --- | --- | --- |
| ii, v, i | E minor | iim7♭5 | F♯m7♭5 to Bm7 to Em7 | F♯m7♭5 opens the phrase |
| vii, I | G major | viim7♭5 | F♯m7♭5 to Gmaj7 | F♯m7♭5 opens the phrase |

## One-edit neighbors

| Becomes | Edit | Changes | Common tones |
| --- | --- | --- | --- |
| F♯dim | 1 ♭3 ♭5 | drops E | 3 |
| F♯m7 | 1 ♭3 5 ♭7 | C becomes C♯ | 3 |
| F♯dim7 | 1 ♭3 ♭5 ♭♭7 | E becomes E♭ | 3 |
| F♯m9 | 1 ♭3 5 ♭7 9 | C becomes C♯, G♯ | 3 |
| F♯m | 1 ♭3 5 | C, E becomes C♯ | 2 |
| F♯7 | 1 3 5 ♭7 | A, C becomes A♯, C♯ | 2 |
| F♯mMaj7 | 1 ♭3 5 7 | C, E becomes C♯, E♯ | 2 |
| F♯aug7 | 1 3 ♯5 ♭7 | A, C becomes A♯, C× | 2 |
| F♯7sus4 | 1 4 5 ♭7 | A, C becomes B, C♯ | 2 |
| F♯m6 | 1 ♭3 5 6 | C, E becomes C♯, D♯ | 2 |

## Set theory

- Absolute pitch classes: {6, 9, 0, 4}
- Relative pitch classes: [0, 3, 6, 10]
- Normal order: [4, 6, 9, 0]
- Prime form: (0258)
- Forte number: 4-27
- Interval vector: <012111>

## Frequencies (close root position)

| Note | MIDI | Frequency |
| --- | --- | --- |
| F♯3 | 54 | 185.00 Hz |
| A3 | 57 | 220.00 Hz |
| C4 | 60 | 261.63 Hz |
| E4 | 64 | 329.63 Hz |

## Questions and answers

### What notes are in F♯m7♭5?

F♯m7♭5 contains F♯, A, C and E. The formula is 1, ♭3, ♭5, ♭7.

### How do you play F♯m7♭5 on piano?

Play F♯, A, C and E together. Right hand fingers 2, 3, 4, 5; left hand 5, 4, 3, 2. F♯ is a black key; A, C and E are white.

### What are the inversions of F♯m7♭5?

4 positions: root position F♯ A C E, F♯m7♭5/A, F♯m7♭5/C, F♯m7♭5/E.

### What keys contain F♯m7♭5?

2: iim7♭5 in E minor, viim7♭5 in G major.

### What is the difference between F♯m7♭5 and F♯dim?

Drops E. 3 of the notes are shared.

### What is an easy F♯m7♭5 for small hands?

The guide tones, ♭3 and ♭7 voicing, A3 E4, spans 7 semitones or about 96 mm.

### What are the frequencies of F♯m7♭5?

From F♯3 at A440 in 12-TET: 185.00, 220.00, 261.63, 329.63 Hz.

### What is the set class of F♯m7♭5?

Prime form (0258), Forte 4-27, interval vector &lt;012111&gt;.

### How do I transpose F♯m7♭5 to another key?

Keep the 1, ♭3, ♭5, ♭7 formula on the new root. Cm7♭5 is C, E♭, G♭, B♭; C♯m7♭5 is C♯, E, G, B.

### Is G♭m7♭5 the same as F♯m7♭5?

Enharmonically yes: the same piano keys and the same sound, spelled differently.

## Provenance

Every derived value above is computed by the piano.org theory kernel from the root, the quality and the stated parameters. Nothing is hand-entered per chord.

Machine record: https://piano.org/api/knowledge/v1/entities/chord:half-diminished-7th:f-sharp
Last reviewed: 2026-08-12