Learn › Inversion Symbols in Music Theory: What 6, 6/4, 6/5, 4/3 and 4/2 Mean
New Released in April 2026
Inversion Symbols in Music Theory: What 6, 6/4, 6/5, 4/3 and 4/2 Mean
The small numbers next to a chord, like 6, 6/4 or 4/3, tell you which note is in the bass. They are intervals counted up from the lowest note. Learn the seven combinations below and you can read the inversion symbols in any music theory book.
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
The full list in one place
- 5/3 (usually left out): triad in root position. C E G.
- 6 (short for 6/3): triad in first inversion, 3rd in the bass. E G C.
- 6/4: triad in second inversion, 5th in the bass. G C E.
- 7: seventh chord in root position. G B D F.
- 6/5: seventh chord in first inversion. B D F G.
- 4/3: seventh chord in second inversion. D F G B.
- 4/2 (or just 2): seventh chord in third inversion, the 7th in the bass. F G B D.
Why the numbers look like that
Each number is the distance from the bass note to another note of the chord. Put E in the bass of a C chord: G is a 3rd above and C is a 6th above, so the chord is 6/3. Writers drop the numbers you can guess, so 6/3 becomes 6 and 6/4/3 becomes 4/3.
Inversion Symbols in Music Theory: What 6, 6/4, 6/5, 4/3 and 4/2 Mean
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 demoA quick way to remember
- Triads: nothing, 6, 6/4. The numbers grow as the bass climbs.
- Seventh chords: 7, 6/5, 4/3, 4/2. Read them as one countdown: 7, 6, 5, 4, 3, 2.
- If you see a 2 anywhere, the 7th is in the bass.
Hear it, then play it
Play C, then C over E, then C over G on a keyboard: same three notes, three different basses. In ChordRunner every inversion counts as the right chord, and an option adds slash chords such as C/E, where the game also checks the bass note. That is the same idea as 6 and 6/4, written the way pop charts write it.
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 do the numbers in chord inversions mean?
They are intervals above the bass note. 6 means a 6th and a 3rd above the bass (first inversion); 6/4 means a 6th and a 4th above it (second inversion). Seventh chords use 7, 6/5, 4/3 and 4/2.
Why is root position not written?
Root position triads are the default, so 5/3 is left out. Seventh chords still show a 7, because the number tells you a 7th is present.
Is C/E the same as C6 in figured bass?
Yes in meaning: both put E under a C chord. Be careful with names, though: in pop symbols C6 is a different chord (C E G A). In figured bass the 6 sits next to a Roman numeral, like I6.
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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