Learn › Cadd9 Chord on Piano (C Add 9)
New Released in April 2026
Cadd9 Chord on Piano (C Add 9)
Cadd9, the C add 9 chord, is the major triad C plus the 9th, D, with no seventh in between. Its notes on the piano are C, E, G and D. Expect a sound that is wide and shiny, a major chord with a ring on top.
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
Where your hand goes for Cadd9
Learn them in pairs: root position first, then the one that keeps the most notes still.
Root position: C D E G
1st inversion: E G C D
2nd inversion: G C D E
Hands and fingers
| Right hand | C D E G | 1 2 3 5 |
|---|---|---|
| Left hand | C D E G | 5 4 3 1 |
The chord hiding inside Cadd9
Take Csus2 (C D G) and add the third E: you have Cadd9. That is why Cadd9 still sounds major, while Csus2 does not.
The formula of Cadd9
Start from C, which you may already know, and change one thing: add D, the 9th, an octave plus a whole step above C.
Start chord: C
| Note | Step | Interval | Keys from C |
|---|---|---|---|
| C | 1 | root | 0 |
| E | 3 | major 3rd | 4 |
| G | 5 | perfect 5th | 7 |
| D | 9 | major 9th | 14 |
Make Cadd9 automatic
- Find C, then add the other notes one at a time: C, E, G and D.
- Switch between C and Cadd9 ten times without looking at your hand.
- Alternate root position and 1st inversion, keeping shared notes still.
- Then test it in random order among other chords: recall under time pressure is what sticks.
Keep each session short and frequent and Cadd9 will become automatic.
Where Cadd9 is used
- Cadd9 fits wherever C fits: C major, G major and F major.
- Pop and worship songs use it in place of plain C to make a simple progression sound fuller.
Turn Cadd9 into a reflex
In ChordRunner every correct chord moves your runner forward. Plug in a MIDI keyboard or let the microphone listen to your piano. Add9 chords come in the level "Sixth & Add Chords".
Play the demoCommon questions
How do you play Cadd9 on the piano?
Press C, E, G and D together. Right hand 1 2 3 5, left hand 5 4 3 1.
Is Cadd9 the same as Csus2?
No. Csus2 has no third, Cadd9 adds E, and that one note makes Cadd9 sound major.
Where is Cadd9 used?
Cadd9 fits wherever C fits: C major, G major and F major. Pop and worship songs use it in place of plain C to make a simple progression sound fuller.
Can I practise Cadd9 with a MIDI keyboard or a real piano?
Yes. In ChordRunner a USB MIDI keyboard is detected automatically, and an acoustic or digital piano works through the microphone. The game checks that C, E, G and D 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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