A Major 9th

Amaj9

Notes

A · C# · E · G# · B

Intervals

  • RootA (1P)
  • Major 3rdC# (3M)
  • Perfect 5thE (5P)
  • Major 7thG# (7M)
  • Major 9thB (9M)

Fretboard

EBGDAE357912EG#ABC#EBC#EG#ABG#ABC#EEG#ABC#ABC#EG#AEG#ABC#E

About

The A major 9th (A–C♯–E–G♯–B) extends a maj7 with a ninth. The result combines the gentle shimmer of the major-7 interval with the openness of the B. The 3rd, 7th, and 9th are the essential tones — the 5th is typically dropped on guitar, since it adds little harmonic information and clutters the voicing. Common in jazz and R&B as a tonic or subdominant color. Compared to AMaj7, maj9 feels more expansive and less static; the added 9th breathes air into the chord without introducing tension. Compared to A6/9, it is more harmonically active because of the 7th.

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