Learn › Cmaj9 Chord on Piano (C Major 9th)
New Released in April 2026
Cmaj9 Chord on Piano (C Major 9th)
The C major 9th chord (Cmaj9) uses the piano keys C, E, G, B and D: the major seventh Cmaj7 plus the 9th, D. Its sound: soft, dreamy and very open.
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
Building Cmaj9 from Cmaj7
Formula 1 3 5 7 9. Count from C and every number is a step of the C major scale, and a b lowers it by one key.
Start chord: Cmaj7
| Note | Step | Interval | Keys from C |
|---|---|---|---|
| C | 1 | root | 0 |
| E | 3 | major 3rd | 4 |
| G | 5 | perfect 5th | 7 |
| B | 7 | major 7th | 11 |
| D | 9 | major 9th | 14 |
Cmaj9 in every position
Each picture is still Cmaj9. Move only the notes that must move.
Both hands: C B E G D
Rootless, 3rd on the bottom: E G B D
Rootless, 7th on the bottom: B D E G
Left hand alone: C B
Which fingers
| Left hand | C B | 5 1 |
|---|---|---|
| Right hand | E G D | 1 2 4 |
A second name for the same keys
Look at the four top notes of Cmaj9: E G B D. They form Em7. So Cmaj9 is C in the bass with Em7 on top, an easy way to find it fast.
When to play Cmaj9
- Cmaj9 is the I chord of C major and the IV chord of G major.
- It replaces Cmaj7 when a song wants a softer, wider sound.
A short Cmaj9 routine
- Find C, then add the other notes one at a time: C, E, G, B and D.
- Switch between Cmaj7 and Cmaj9 ten times without looking at your hand.
- Alternate root position and a rootless shape with the 3rd on the bottom, keeping shared notes still.
- Then test it in random order among other chords: recall under time pressure is what sticks.
Come back to Cmaj9 tomorrow: short daily sessions beat one long one.
Train Cmaj9 with ChordRunner
ChordRunner shows a chord symbol and you play it on a MIDI keyboard, a real piano through the microphone or the on-screen keys. Major and minor 9ths have their own level, "Ninth Chords".
Play the demoCommon questions
What notes are in the Cmaj9 chord?
Cmaj9 has 5 notes: C, E, G, B and D. Formula 1 3 5 7 9.
Is Cmaj9 the same as Em7?
Not quite: Em7 (E G B D) is only the upper part of Cmaj9. Add C underneath and you have the full Cmaj9.
Where is Cmaj9 used?
Cmaj9 is the I chord of C major and the IV chord of G major. It replaces Cmaj7 when a song wants a softer, wider sound.
Can I practise Cmaj9 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, B 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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