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A♯m7♭5 Chord: Guitar, Piano and Notes

The A♯m7♭5 chord is a half-diminished chord built on the root note A♯. Its notes are A♯, C♯, E and G♯. It's enharmonically the same chord as B♭m7♭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
A♯ · C♯ · E · G♯
Formula
1 · ♭3 · ♭5 · ♭7
Semitones
0 · 3 · 6 · 10
Note
A♯
Quality
Half-Diminished (m7♭5)
Symbol
A♯m7♭5

A♯m7♭5 on piano

4 notes
View:
Piano diagram of the A♯m7♭5 chord

Switch to the interactive diagram to hear the chord, change voicing and swap finger numbers for note names.

To play A♯m7♭5 on piano, place your right hand with your thumb on A♯, index finger on C♯, middle finger on E and little finger on G♯. Press the keys together and listen for an even sound. On the keyboard A♯, C♯ and G♯ are black keys and E is white. The thumb starts on a black key, so slide the whole hand a little further in, towards the fallboard. Practice moving in and out of the chord slowly, then bring in a metronome.

  • A♯1
  • C♯♭3
  • E♭5
  • G♯♭7

A♯m7♭5 on guitar

View:
Guitar chord diagram of the A♯m7♭5 chord

Switch to the interactive diagram to hear the chord, change voicing and swap finger numbers for note names.

On guitar, A♯m7♭5 is commonly played with the voicing shown above. This one is a barre at fret 6: 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.

A♯ · C♯ · E · G♯

Play A♯m7♭5 on the online piano

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A♯m7♭5 chord notes

Also known as B♭m7♭5

DegreeIntervalSemitonesNoteHear
1Root0A♯(A#)
♭3Minor third3C♯(C#)
♭5Diminished fifth6E
♭7Minor seventh10G♯(G#)

How to use the A♯m7♭5 chord

The A♯m7♭5 chord is built from a root, a minor third, a diminished fifth and a minor seventh. Start at the root A♯ and stack the intervals to get the whole chord: A♯, C♯, E and G♯. 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 A♯m7♭5 is the viiø7 in B major; in minor keys it's the iiø7 in G♯ minor.

How A♯m7♭5 differs from similar chords

A♯m7♭5 differs from A♯m7 by one lowered note, the fifth, and from A♯°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 A♯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 ii in a minor ii-V-iG♯ minor
  1. iiø7A♯m7♭5
  2. V7D♯7
  3. iG♯m

The minor cadence. A♯m7♭5 leads into the dominant, and the seventh is what makes it a ii rather than a diminished triad.

As the leading-tone chordB major
  1. viiø7A♯m7♭5
  2. Imaj7Bmaj7

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 A♯m7♭5 chord?
The A♯m7♭5 chord contains A♯, C♯, E and G♯ (A#, C#, E and G# in plain text).
Is the A♯m7♭5 chord major or minor?
A♯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 A♯m7♭5 chord in?
In major keys A♯m7♭5 is the viiø7 in B major; in minor keys it's the iiø7 in G♯ minor.
How do you play A♯m7♭5 on piano?
Place your fingers on A♯, C♯, E and G♯ 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 A♯, C♯ and G♯ are black keys and E is white. The thumb starts on a black key, so slide the whole hand a little further in, towards the fallboard.
How do you play A♯m7♭5 on guitar?
Use the fingering in the diagram above. This one is a barre at fret 6: 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 A♯m7♭5 chord?
A♯m7♭5 is enharmonically equivalent to B♭m7♭5. Both chord names describe exactly the same notes, but the spelling depends on the key you are playing in.