How to Play 9, 11 and 13 Chords on Piano (Extended Harmony)
To play 9th, 11th and 13th chords on piano, make sure a seventh is present, then add the extension using shortcuts such as a 3-7 shell voicing with a note on top, a triad over a different bass (for example Gm/C for C9), two triads stacked as a polychord, or quartal and quintal stacks.
Key points
- A chord needs a seventh before you call it a 9, 11 or 13; without one it is an add chord.
- The 9 is the 2, the 11 is the 4 and the 13 is the 6, heard alongside the seventh.
- Shell voicings (3 and flat 7) leave fingers free to add 9, b9, #9, 13 or b13.
- Slash chords and polychords build extensions from familiar triads, e.g. Gm/C for C9 and F major under G minor for Gm11.
- Quartal (fourths) and quintal (fifths) stacks give open, ambient extended sounds.
This lesson by Jason Zac of Nathaniel School of Music explains what ninth, eleventh and thirteenth chords are. It then shows five practical ways to play them on the piano without spelling out long stacks of thirds. It suits players who already know major and minor triads, basic intervals and the major scale.
The essential theory of extensions
A chord can only be called a 9, 11 or 13 if it contains a seventh. That can be a major seventh (C to B) or a minor seventh, also called the dominant seventh (C to Bb).
- 9 is the same note as the 2. Without a seventh, C E G D is C add9 (or add2). With Bb added it becomes C9. With B it becomes Cmaj9.
- The 9 can be altered: C7b9 (Db) has a dark, diminished sound, often heard in harmonic minor. C7#9 (D#) sounds jazzy and works in rock too. The altered 9ths sit best with a flat 7. The plain 9 also works with a major 7.
- 11 is the perfect fourth (F) alongside the seventh. #11 (F#) sounds great with a flat 7 and even with a major 7.
- 13 is the sixth (A) alongside the flat 7. b13 (Ab) is the same sound as #5, so C7b13 and C7#5 overlap. Likewise C7b5 and C7#11 are interchangeable names.
- There is no #13 because it duplicates the flat 7. There is no b11 because it is simply the major third.
Method 1: Fifth chord on top, explore the bass
Hold a fifth chord in the right hand, such as D5 (D A D). Move the left hand through different bass notes:
- Bb gives a Bbmaj7 sound.
- F gives an F6 sound.
- E gives an E7sus4 sound.
- Eb gives a Lydian, maj7#11 colour.
Some bass notes, such as Ab, are too dissonant to use. Next, add a flat 7 above the bass. With C and Bb in the left hand, the right-hand D becomes the 9 and the A becomes the 13. You can also try a 6 instead of the flat 7.
Method 2: The 3-7 voicing
Play C in the left hand. In the right hand play the 3 and flat 7, either E and Bb or Bb and E. Free fingers can now add extensions:
- Add D on top for C9.
- Lower it to Db for C7b9, or raise it to D# for C7#9.
- Change the shell to get maj9, minor 9 and minor-major 9 chords.
- Move the Bb down into the left hand and use the right-hand finger for the 13 (A) or the b13 (Ab).
This gives a clean sound that works well in the blues.
Method 3: Slash chords
Use triads you already know over a different bass note.
- Major 7th: go up a major third from the root and play a minor triad. So Em/C gives Cmaj7, Dm/Bb gives Bbmaj7, and Gm/Eb gives Ebmaj7.
- 9th sound: go up a fifth and play a minor triad. Gm/C gives C with b7 and 9.
- Dominant 9 and 11: play a major triad a tone below the root. Bb/C is common in gospel and musicals, and is useful for modulating or for a vocal run.
- 9, #11, 13: D/C gives a Lydian sound.
- 9, 11, 13: Dm/C works, ideally with the flat 7 added.
Method 4: Polychords
Stack two triads. Play a minor triad, then a major triad a tone below it. G minor over F major gives G Bb D F A C, which is Gm11. C minor over Bb major gives Cm11, a dreamy, ambient sound. Two instruments can share the two triads when you arrange.
Method 5: Quartal and quintal voicings
Quartal chords stack fourths instead of thirds, for example C F Bb. There are three types:
- perfect fourth plus perfect fourth
- perfect fourth plus augmented fourth
- augmented fourth plus perfect fourth
Build them on each note of a scale such as C Dorian. Over a C minor chord you get a line of colourful 9, 11 and 13 sounds.
Quintal chords stack perfect fifths, such as C G D, which already gives a ninth sound. This is different from a fifth chord, which is root, fifth and octave. Quintal chords sound open and ambient, even low in the left hand.
How to practise
Take one method at a time and try it in several keys. For quintal voicings, move backwards around the Circle of Fifths (F, Bb, Eb, Ab, Db). Listen to the flavour each extension brings, and use the shapes for improvising and composing.
Questions about this lesson
What is the difference between C add9 and C9?
C add9 is a C major triad with D and no seventh. Once the flat 7 (Bb) is present, the chord is called C9.
Why is there no sharp 13 or flat 11 chord?
A sharp 13 is the same note as the flat 7, so it is already in the chord. A flat 11 is the same as the major third.
What is the quickest way to play a minor 11th chord on piano?
Play a minor triad in the right hand and a major triad a tone below it in the left hand. For example, F major under G minor gives Gm11.
How do I play a major 7th chord using slash chords?
Play the root in the bass and a minor triad starting a major third above it. Em over C gives Cmaj7, and Gm over Eb gives Ebmaj7.
Practise it
- Voicing RoomA hands-on lesson room for piano chord voicings.
- Jazz Harmony LabPractise jazz shell voicings, guide-tone movement and comping through changing keys.
- Piano classes at Nathaniel School of MusicLive online or in Bangalore, with a teacher.
- All free music apps40 practice tools for harmony, rhythm, ear training and more.
Related lessons
- Slash Chords on Piano: Add Rich Colour With One Bass-Note TrickA slash chord is a familiar triad played over a different bass note, and on piano you can enrich a progression like D–Bm–Em–A by keeping the bass note and playing the triad built a fifth above it, which brings out 7ths and 9ths automatically.
- 5 Piano Chord Voicings That Instantly Sound Richer: Spread, Slash, Add9, 7ths and QuartalTo make simple piano chords sound richer, take a progression like G–Em–Am–D and replay it with spread (open) voicings, slash chords, stacked-fifth add9 shapes, 1-5 plus 3-7 seventh voicings, or quartal chords built in fourths.
- 5 Simple Ways to Make Your Chords Colourful Without ExtensionsYou can make simple major and minor triads sound colourful on piano, without sevenths or jazz extensions, by using five voicing techniques: static fifth chords, add2 and add4 chords, slash chords, spread voicings, and quartal or quintal voicings.
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