As the ii in a minor ii-V-iA♯ minor
The minor cadence. B♯m7♭5 leads into the dominant, and the seventh is what makes it a ii rather than a diminished triad.
B♯m7♭5 Chord: Guitar, Piano and Notes
The B♯m7♭5 chord is a half-diminished chord built on the root note B♯. Its notes are B♯, D♯, F♯ and A♯. It's enharmonically the same chord as Cm7♭5.
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Short answer
Half-diminished chords (m7♭5) sit between a diminished triad and a minor seventh. They're the signature ii chord in minor keys and show up constantly in jazz standards and moody ballads.
- Notes
- B♯ · D♯ · F♯ · A♯
- Formula
- 1 · ♭3 · ♭5 · ♭7
- Semitones
- 0 · 3 · 6 · 10
- Note
- B♯
- Quality
- Half-Diminished (m7♭5)
- Symbol
- B♯m7♭5
B♯m7♭5 on piano
4 notesView:
Switch to the interactive diagram to hear the chord, change voicing and swap finger numbers for note names.
To play B♯m7♭5 on piano, place your right hand with your thumb on B♯, index finger on D♯, middle finger on F♯ and little finger on A♯. Press the keys together and listen for an even sound. On the keyboard D♯, F♯ and A♯ are black keys and B♯ is white, the key you'd normally call C. Practice moving in and out of the chord slowly, then bring in a metronome.
- B♯1
- D♯♭3
- F♯♭5
- A♯♭7
B♯m7♭5 on guitar
View:
Switch to the interactive diagram to hear the chord, change voicing and swap finger numbers for note names.
On guitar, B♯m7♭5 is commonly played with the voicing shown above. This one is a barre at fret 8: keep the index finger flat across the strings and curve the others so they don't mute the strings next to them. Don't play strings 2 and 1.
B♯ · D♯ · F♯ · A♯
Try B♯m7♭5 on the virtual piano
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B♯m7♭5 chord notes
Also known as Cm7♭5
| Degree | Interval | Semitones | Note | Hear |
|---|---|---|---|---|
| 1 | Root | 0 | B♯(B#) | |
| ♭3 | Minor third | 3 | D♯(D#) | |
| ♭5 | Diminished fifth | 6 | F♯(F#) | |
| ♭7 | Minor seventh | 10 | A♯(A#) |
How to use the B♯m7♭5 chord
The B♯m7♭5 chord is built from a root, a minor third, a diminished fifth and a minor seventh. Start at the root B♯ and stack the intervals to get the whole chord: B♯, D♯, F♯ and A♯. The same formula gives you the chord in any other key.
Half-diminished chords are most common in jazz standards. They frequently act as the iiø of a minor ii-V-i, leading into the dominant that resolves to a minor tonic.
In major keys B♯m7♭5 is the viiø7 in C♯ major; in minor keys it's the iiø7 in A♯ minor.
How B♯m7♭5 differs from similar chords
B♯m7♭5 differs from B♯m7 by one lowered note, the fifth, and from B♯°7 by one raised note, the seventh. That in-between position is where the name half-diminished comes from. In a minor key it is the ii chord, so it almost always leads to a dominant seventh.
Where B♯m7♭5 is used
A half-diminished seventh has one main use: it is the ii of a minor key, leading into the dominant. A major key builds the same chord on its seventh degree.
As the leading-tone chordC♯ major
- viiø7B♯m7♭5
- Imaj7C♯maj7
The chord a major key builds on its seventh degree, resolving up a semitone onto the tonic.
Questions people ask
- What notes are in the B♯m7♭5 chord?
- The B♯m7♭5 chord contains B♯, D♯, F♯ and A♯ (B#, D#, F# and A# in plain text).
- Is the B♯m7♭5 chord major or minor?
- B♯m7♭5 is a half-diminished chord. Half-diminished chords (m7♭5) sit between a diminished triad and a minor seventh. They're the signature ii chord in minor keys and show up constantly in jazz standards and moody ballads.
- What key is the B♯m7♭5 chord in?
- In major keys B♯m7♭5 is the viiø7 in C♯ major; in minor keys it's the iiø7 in A♯ minor.
- How do you play B♯m7♭5 on piano?
- Place your fingers on B♯, D♯, F♯ and A♯ and play them together. The root usually goes to the little finger of the left hand, the upper notes to the right. On the keyboard D♯, F♯ and A♯ are black keys and B♯ is white, the key you'd normally call C.
- How do you play B♯m7♭5 on guitar?
- Use the fingering in the diagram above. This one is a barre at fret 8: keep the index finger flat across the strings and curve the others so they don't mute the strings next to them. Don't play strings 2 and 1.
- What is another name for the B♯m7♭5 chord?
- B♯m7♭5 is enharmonically equivalent to Cm7♭5. Both chord names describe exactly the same notes, but the spelling depends on the key you are playing in.