Learn › A Half-Diminished Chord on Piano (Am7b5)
New Released in April 2026
A Half-Diminished Chord on Piano (Am7b5)
The A half-diminished 7th chord (Am7b5) on the piano has four notes: A, C, Eb, G. It is an Adim triad with a minor seventh, G, on top. Formula 1 b3 b5 b7. Learn the shape and the inversions, then practise Am7b5 by playing.
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- MIDI keyboard
- Digital or acoustic piano
- Guitar
- Computer, phone or tablet
A half-diminished 7th chord inversions
A seventh chord has four notes, so it has four positions. Each one is still Am7b5.
Root position: A C Eb G
1st inversion: C Eb G A
2nd inversion: Eb G A C
3rd inversion: G A C Eb
Playing Am7b5 with each hand
| Hand | A | C | Eb | G |
|---|---|---|---|---|
| Right hand | 1 (thumb) | 2 | 3 | 5 (little) |
| Left hand | 5 (little) | 3 | 2 | 1 (thumb) |
Too much stretch? Play A alone in the left hand and C Eb G in the right.
A three-note Am7b5
Leave out the third (C) and keep A Eb G. The flat fifth carries the half-diminished sound and the hand stays compact.
How Am7b5 differs from the other 7th chords on A
Play the four in a row and listen to each colour.
How to practise Am7b5
- Play A, C, Eb, G slowly in root position and say "Am7b5" each time.
- Walk up through the inversions (C Eb G A, Eb G A C, G A C Eb) without lifting the whole hand.
- Play it in its ii-V-I, Am7b5 → D7 → Gm, four beats per chord.
- Finally meet it in random order between other chords, with a check on every note.
Short daily rounds fix Am7b5 in memory faster than one long practice a week.
Make Am7b5 automatic
In ChordRunner Am7b5 and every other chord ride towards your runner: play them in time. MIDI keyboard or microphone, both work.
Play the demoCommon questions
What is the difference between Am7b5 and Adim?
Am7b5 adds one note to the Adim triad: G, the minor seventh. That fourth note is what makes it a seventh chord.
What are the inversions of Am7b5?
Root position A C Eb G, 1st inversion C Eb G A, 2nd inversion Eb G A C and 3rd inversion G A C Eb. Every position is still Am7b5.
Where does Am7b5 go?
Am7b5 is the iiø7 of G minor and the viiø7 of Bb major. In a minor ii-V-i it opens the cadence: Am7b5 → D7 → Gm.
Can I practise Am7b5 with a MIDI keyboard?
Yes. In ChordRunner a USB MIDI keyboard is detected automatically, and an acoustic piano works through the microphone. Am7b5 counts in any inversion, as long as A, C, Eb, G sound together.
Your instrument is the controller.
ChordRunner is a browser game that teaches piano and guitar chords: a chord appears on screen, you play it on a real instrument, and your runner jumps. MIDI keyboard or microphone, both work.
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