Learn › B Diminished 7th Chord on Piano (Bdim7)
New Released in April 2026
B Diminished 7th Chord on Piano (Bdim7)
To play Bdim7 on the piano, press B, D, F, Ab together: root, minor third, flat fifth and diminished seventh. Take Bdim and add Ab. Below: the four positions, fingering, a three-note voicing and where Bdim7 goes next.
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- MIDI keyboard
- Digital or acoustic piano
- Guitar
- Computer, phone or tablet
Four ways to play Bdim7
Move B up an octave for the 1st inversion, then D for the 2nd, then F for the 3rd.
Root position: B D F Ab
1st inversion: D F Ab B
2nd inversion: F Ab B D
3rd inversion: Ab B D F
Playing Bdim7 with each hand
| Hand | B | D | F | Ab |
|---|---|---|---|---|
| Right hand | 1 (thumb) | 2 | 3 | 5 (little) |
| Left hand | 5 (little) | 3 | 2 | 1 (thumb) |
Play Bdim7 broken first, B, D, F, Ab one by one, then together: a wrong key stands out.
A three-note Bdim7
Root, third, seventh: B D Ab. It is the shape to learn first, and it moves smoothly to the next chord.
How Bdim7 differs from the other 7th chords on B
Play the four in a row and listen to each colour.
Where Bdim7 goes
- Bdim7 is the vii°7 chord of C minor: it pulls up one key, Bdim7 → C / Cm.
- Every note is three keys above the one before, so Bdim7, Ddim7, Fdim7 and Abdim7 use the same four keys.
- That even spacing is why Bdim7 sounds tense, dramatic and can lead to several different chords.
vii°7 → i: Bdim7 → Cm
How to practise Bdim7
- Play B, D, F, Ab slowly in root position and say "Bdim7" each time.
- Walk up through the inversions (D F Ab B, F Ab B D, Ab B D F) without lifting the whole hand.
- Play it in its ii-V-I, Bdim7 → Cm, four beats per chord.
- Finally meet it in random order between other chords, with a check on every note.
Short daily rounds fix Bdim7 in memory faster than one long practice a week.
Practise Bdim7 by playing
In ChordRunner Bdim7 and every other chord ride towards your runner: play them in time. MIDI keyboard or microphone, both work.
Play the demoCommon questions
How do you play Bdim7 on the piano?
Press B, D, F, Ab together. Right hand 1, 2, 3, 5 with the thumb on B; any octave and any order of those notes is still Bdim7.
What are the inversions of Bdim7?
Root position B D F Ab, 1st inversion D F Ab B, 2nd inversion F Ab B D and 3rd inversion Ab B D F. Every position is still Bdim7.
Where does Bdim7 go?
Bdim7 is the vii°7 chord of C minor: it pulls up one key, Bdim7 → C / Cm. Every note is three keys above the one before, so Bdim7, Ddim7, Fdim7 and Abdim7 use the same four keys.
Can I practise Bdim7 with a MIDI keyboard?
Yes. In ChordRunner a USB MIDI keyboard is detected automatically, and an acoustic piano works through the microphone. Bdim7 counts in any inversion, as long as B, D, F, Ab 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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