Add 11

Notes and formula

The formula is 1 – 3 – 5 – 11, or 0 – 4 – 7 – 17 in semitones. The eleventh is a fourth raised by an octave, and the octave is doing essential work.

Fold the F down beside the E and the chord is unplayable. Left an eleventh above the root it is merely tense — the same interval, spread far enough apart that the ear hears two voices rather than a collision.

How to play it

On guitar the shape is x–3–2–0–x–1, sounding C–E–G–F with the eleventh on the top string, an octave and a fourth above the root. The wide spacing is not optional here — it is what makes the chord work.

On piano keep the triad in the left hand and the F alone at the top of the right. Any voicing that puts the F within an octave of the E produces a chord most listeners will hear as an error.

Add11 or sus4

Csus4 is C–F–G: the fourth replaces the third and the chord has no quality. Cadd11 keeps the third and adds the fourth above it, so the chord stays firmly major and acquires tension instead of losing it.

This is the distinction the two symbols exist to make, and it is worth reading carefully: a guitarist who plays sus4 for add11 removes the note that makes the chord bright.

Where you hear it

In worship and stadium-rock guitar, where an open high string ringing a fourth above a fretted triad is a signature sound. In film scoring, as a major chord with an unresolved edge.

It is rare on piano for the reason described above — the instrument makes the close voicing too easy and the wide one deliberate.

Add11 or add♯11

Raise the eleventh a semitone and the friction disappears entirely: Cadd♯11 is C–E–G–F♯, a Lydian triad with no clash anywhere.

The two chords sound completely different despite differing by one semitone. Add11 is tense and modal; add♯11 is bright and floating. Choosing between them is a real decision, not a spelling preference.

Scales that contain it

Ionian and Mixolydian both fit — the chord needs a major third, a perfect fifth and a natural fourth, and says nothing about the seventh.

Lydian does not fit: it raises the fourth, which is the chord's defining added note. That is worth noticing, because Lydian suits almost every other major chord in the catalogue.

Frequently asked questions