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New Released in April 2026
Half Diminished vs Fully Diminished Seventh Chords
Half diminished vs fully diminished comes down to one note, the 7th. Both start with a diminished triad, B D F. Add A and you get Bø7, half diminished. Lower that A to Ab and you get B°7, fully diminished.
No account, no download. The demo has limited content. Advanced features are in ChordRunner Premium.
- MIDI keyboard
- Digital or acoustic piano
- Guitar
- Computer, phone or tablet
Side by side
- Bø7 (Bm7b5): B D F A. A diminished triad plus a minor 7th.
- B°7 (Bdim7): B D F Ab. A diminished triad plus a diminished 7th, which sounds like a major 6th.
- Same first three notes, different top note.
Symbols you will meet
- Half diminished: ø7, m7b5, min7(b5), -7b5.
- Fully diminished: °7, dim7.
- A plain ° or dim with no 7 is only the triad.
Half Diminished vs Fully Diminished Seventh Chords
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.
Play the demoWhere each one lives
In a major key the chord on the 7th degree is half diminished: Bø7 in C major. In a minor key, ii is half diminished (Dø7 in C minor) and, with the raised 7th, the chord on the 7th degree is fully diminished (B°7 in C minor). That is why jazz players call the minor ii-V-i "half diminished to dominant".
Hear the difference, then play it
Half diminished sounds dark but soft, a minor 7th chord with a lowered 5th. Fully diminished is tense and symmetrical: every note is a minor 3rd from the next, so there are only three different dim7 chords. ChordRunner has both, m7b5 and dim7, in its chord set, so you can drill them in all 12 keys on a MIDI keyboard or through the microphone.
The levels in ChordRunner
- Beginner: major, minor, augmented and diminished chords.
- Intermediate: adds sus2 and sus4.
- Advanced: adds 6th, 7th and 9th chords.
- Pro: adds 11th, 13th and altered chords; an adaptive mode adds the next family when you are ready.
Common questions
What is the difference between half diminished and fully diminished?
The 7th. Half diminished has a minor 7th (B D F A); fully diminished has a diminished 7th, one half step lower (B D F Ab).
Is m7b5 the same as half diminished?
Yes. Bm7b5 and Bø7 are two names for the same chord: B D F A.
Why are there only three diminished seventh chords?
Because the chord is built from equal minor 3rds. Bdim7, Ddim7, Fdim7 and Abdim7 share the same four notes, so 12 roots give only three different sets.
Which instruments work?
A USB MIDI keyboard, detected automatically, or a piano or guitar through the microphone. Everything runs in Chrome or Edge on a computer, tablet or phone.
How is this different from apps where you tap the screen?
Tapping trains your eyes and fingers on glass. Here you press real keys or fret real strings, and the game hears the actual notes, so what you practise is exactly what you will play on your instrument.
Is everything in the demo?
The demo has limited content. Advanced features are in ChordRunner Premium.
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.
Try the demoKeep learning
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