B♭ Added 9th Chord

Chord Tones: B♭ Added 9th Chord

Symbol: add9, add2 — Formula: 1-3-5-9

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 B♭ add9 chord commonly functions as the subtonic (♭VII) in C major or subdominant in F major. Its harmonic role varies by key — in major keys it provides stable harmonic grounding.

The add9 chord adds a ninth (octave + second) to a major triad without including the seventh. It has a bright, open sound, richer than a plain major chord but less complex than a major ninth. The B♭ Added 9th Chord specifically contains 4 notes: B♭, D, F, C (formula: 1-3-5-9). On piano, Bb-rooted chords start on a black key and create hand shapes that jazz pianists find ideal for voicing seventh chords and extended harmonies. Jazz standards, swing, and big band charts are heavily weighted toward Bb because it allows horn sections to play in their most comfortable range.

Common Progressions

The B♭ Added 9th Chord frequently appears in these progression patterns (shown in Roman numeral notation relative to key):

• Iadd9-IVadd9
• Iadd9-V

Songs Featuring the Added 9th Chord

Well-known songs where the B♭ Added 9th Chord — or this chord type — plays a prominent role:

• Every Breath You Take – The Police
• With or Without You – U2
• Right Here Waiting – Richard Marx

Tuning Frequencies Across Temperaments

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

Scales Containing the B♭ Added 9th Chord

These scales include the B♭ Added 9th Chord as a diatonic or characteristic chord: