C Major Ninth Chord

Chord Tones: C Major Ninth Chord

Symbol: maj9, M9, △9 — Formula: 1-3-5-7-9

Chord Notation

Roman numeral (e.g. I, IV, V) and Nashville Number notation are key-dependent. See Keys pages for chord function within specific keys.

Inversions

Harmonic Function

The C major ninth chord commonly functions as the tonic (I) in C major/minor. Its harmonic role varies by key — in major keys it provides stable harmonic grounding.

The major ninth chord extends the major seventh with a ninth, creating a lush, sophisticated sound central to jazz and R&B. It conveys spaciousness, warmth, and harmonic richness. The C Major Ninth Chord specifically contains 5 notes: C, E, G, B, D (formula: 1-3-5-7-9). On piano, C-rooted chords sit entirely on white keys in their basic triad form, making them the first chords most students learn. Pop, folk, and singer-songwriter music heavily use C-rooted chords because open-position guitar voicings and piano shapes are immediately accessible.

Common Progressions

The C Major Ninth Chord frequently appears in these progression patterns (shown in Roman numeral notation relative to key):

• Imaj9-IVmaj9
• Imaj9-ii7

Songs Featuring the Major Ninth Chord

Well-known songs where the C Major Ninth Chord — or this chord type — plays a prominent role:

• Nights in White Satin – Moody Blues
• Clair de Lune – Debussy (adapted)
• Once in a While – jazz standard

Tuning Frequencies Across Temperaments

Frequencies shown at A=440 Hz. View full temperament data for any note.

Scales Containing the C Major Ninth Chord

These scales include the C Major Ninth Chord as a diatonic or characteristic chord: