Chords
Extended chords (9, 11, 13)
An extended chord continues a seventh chord by stacking thirds beyond the seventh: the ninth, eleventh and thirteenth, as in C9, Am11 or G13.
What are extended chords?
A seventh chord stacks three thirds: 1, 3, 5, 7. Keep stacking thirds and you get the extensions: the 9, 11 and 13. They are scale degrees 2, 4 and 6, played an octave higher.
| Extension | Same note as | On C |
|---|---|---|
| 9 | 2 | D |
| 11 | 4 | F |
| 13 | 6 | A |
The naming rule: the highest number implies the seventh (and, in theory, the lower extensions). C13 is C E G B♭ D F A on paper. With no seventh, you have an add9 chord or a sixth chord (C6) instead.
Which notes do you leave out on six strings?
A full C13 has seven notes, which no guitarist can play cleanly. Keep what matters:
- Always: the third and the seventh, which define the chord quality.
- The named extension: the 13 in a 13 chord, the 11 in an 11 chord.
- Optional: the root (often covered by the bass player) and the fifth, which goes first.
Watch out for the natural 11 on major and dominant chords: F rubs a half step against the E of the third. On those chords, guitarists play the #11 (Cmaj7#11) or drop the third (C11 = C9sus4, often written B♭/C: x3333x). On a minor chord the 11 is natural and sounds great.
Extended chord shapes to know
Each fingering is a partial voicing, checked string by string:
| Chord | Fingering | Notes (low to high) |
|---|---|---|
| C9 | x32333 | C E B♭ D G |
| Cmaj9 | x3243x | C E B D |
| Dm9 | x5355x | D F C E |
| Am11 | 5x553x | A G C D |
| G13 | 3x345x | G F B E |
| C13 | x32355 | C E B♭ E A |
Notice that G13 uses only four fingers: root, seventh, third and thirteenth. The fifth and ninth are gone, yet your ear still hears the full colour.
Example: an extended ii-V-I in C major
Play Dm9 (x5355x), G13 (3x345x), Cmaj9 (x3243x), one bar each. The voices barely move:
- F on the D string, 3rd fret, holds from Dm9 to G13, then drops to E (2nd fret) on Cmaj9.
- On the G string, C (5th fret) slides down to B (4th fret) and stays there.
- On the B string, E (5th fret) holds through G13, then falls to D (3rd fret).
That is the stock sound of jazz and soul. Compare it with plain Dm7, G7, Cmaj7 to hear what the extensions add. Extending chords is often the first step of a reharmonization, and the chord substitutions tool gives playable voicings for each replacement.
Key takeaways
- 9 = 2, 11 = 4, 13 = 6, an octave up, on top of a seventh.
- Keep the third, seventh and extension, drop the fifth first.
- On major and dominant chords, prefer #11 to a natural 11.
- On an altered dominant, the extensions become ♭9, #9 and ♭13.
Frequently asked questions
What is the difference between C6 and C13?
Both contain A. C6 (C E G A) has no seventh and sounds settled, like a tonic chord. C13 contains B♭, so it is a dominant chord that wants to resolve to F.
Do you have to play the root of an extended chord?
Not necessarily. In a band the bass player already covers it, and leaving it out frees a finger for the extension. When playing solo, keep it at first so the ear understands the chord, then try rootless voicings.
Does a 9 chord always include a seventh?
Yes. C9 means C7 plus the ninth (C E G B♭ D), Cmaj9 specifies a major seventh and Cm9 a minor third. If a chart wants a ninth without a seventh, it writes Cadd9.
Related terms
Practise in the workshop
Take it from theory to the fretboard
Open the workshop tools and see this idea across the whole neck. Free account, no card needed.