F♯ Added 9th Chord

Chord Tones: F♯ 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 F♯ add9 chord commonly functions as the tritone substitution in C major or tonic 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 F♯ Added 9th Chord specifically contains 4 notes: F♯, A♯, C♯, G♯ (formula: 1-3-5-9). On piano, F#-rooted chords place the root on a black key, creating hand positions that many pianists find ergonomically comfortable for fast passages. Progressive rock, jazz fusion, and electronic music use F#-rooted chords to create unexpected harmonic shifts and chromatic modulations.

Common Progressions

The F♯ 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 F♯ 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 F♯ Added 9th Chord

These scales include the F♯ Added 9th Chord as a diatonic or characteristic chord: