B♭ Half Diminished
Also Known As
Hear the B♭ Half Diminished chord played for you.
B♭ø7
B♭ – D♭ – E – A♭
Formula:R-m3-d5-m7
Intervals:P1-m3-d5-m7
Scale Degrees:1-b3-b5-b7
Introduction
The B♭ Half Diminished chord is a four-note chord made up of B♭, D♭, E, and A♭. It is built from a root, minor third, diminished fifth, and minor seventh.
The Bb Half Diminished piano chord (Bbm7b5) consists of the notes Bb, Db, E, Ab. It is a diminished triad with an added minor 7th, giving it a dark, moody, and tense character commonly used in jazz and minor key progressions. Formula: R-m3-d5-m7 | Scale degrees: 1-b3-b5-b7.
Notes
B♭ Half Diminished Inversions
| Position | Notes |
|---|---|
| Root Position | Bb – Db – E – Ab |
| 1st Inversion | Db – E – Ab – Bb |
| 2nd Inversion | E – Ab – Bb – Db |
| 3rd Inversion | Bb – Db – E – Ab |
Key Signature
The key of Bb Half Diminished has 2 flats.
B♭E♭
Order of flats
Flats are added in a fixed order — the reverse of the sharp order. Each new flat key adds the next flat on the list.
B♭E♭A♭D♭G♭C♭F♭
Mnemonic: Battle Ends And Down Goes Charles’ Father
Chords in the Key of Bb Major
These are the diatonic triads built on each degree of the Bb major scale:
C
D
E
F
G
A
B
C
D
E
F
G
A
B
I — B♭ Major (major)
Theory: Intervals
Formula: R-m3-d5-m7
Intervals: P1-m3-d5-m7
The B♭ Half Diminished is built by stacking intervals from the root note. The formula R-m3-d5-m7 describes the scale degrees used. The intervals P1-m3-d5-m7 show the distance between each note in the chord.
B♭ Half Diminished — Frequently Asked Questions
What notes are in the Bb Half Diminished chord?
Bbm7b5 contains: Bb, Db, Fb, Ab. Diminished triad with minor seventh.
How does Bbm7b5 differ from Bbdim7?
Minor seventh (Ab) vs diminished seventh (Abb/G).
How is Bbm7b5 used?
ii chord in Ab minor.
What songs use Half Diminished?
Jazz minor-key harmony.
How does Bbm7b5 differ from Bbm7?
Flatted fifth (Fb vs F).
Is Bbm7b5 the same as Dbm6?
Same notes, different root.
Practice Tips
- Minor-key ii–V–i: Bbm7b5 → Eb7 → Abm.
- Bbm7b5 and Dbm6 same notes.
- Compare with Bbdim7 and Bbm7.
- Jazz vocabulary.
- All flats.
- The Fb creates tension.
Related Tools
Chord FinderLook up any chord — see the notes, hear it, and play along.Chord DrillTimed drills to build speed and recognition across all chord types.Practice RoomPlug in a MIDI keyboard and get real-time feedback on every chord and scale.Circle of FifthsVisualize key relationships, relative minors, and key signatures.MIDI MonitorLive MIDI message stream with note names, velocity, and a scrolling staff.