A#13 Chord on Guitar
A#13 = A# – D – F – G# – C – G (Root, Major 3rd, Perfect 5th, Minor 7th, Major 9th, Major 13th)
A#13, or Bb13, is the biggest extended dominant chord in this set, theoretically stacking a thirteenth above a full dominant ninth, but the sixth-fret guitar barre trims that down by dropping the ninth and eleventh outright. What's left resembles A#7 with a sixth-string sixth laid on top — a compact stand-in for the chord's fuller jazz color.
Full theory calls for A#, D, F, G#, C, G, but the working voicing leans on root, third, flat seventh, and thirteenth — A#, D, G#, G — the same top note that defines A#6. That overlap isn't coincidence: a dominant thirteenth is essentially a dominant seventh with a sixth-like note stacked above it, which is exactly why the two shapes sit so close together on the fretboard. As V13 it resolves to D#/Eb major with the same underlying pull as A#7, just carrying a richer, more jazz-inflected color suited to swing and bossa-influenced guitar parts.
Fingerings
Barre (6th fret)
How to Practice It
Compare this shape side by side with A#6, since the two share a top note and much of their fingering — the difference is which string carries the flat seventh instead of a plain triad tone. Slowly working the move from A#13 into D#/Eb major helps the ear catch that top G resolving, even though it isn't stepping down the way a ninth typically would.
Common Progressions
- A#13 – D# (V13 – I, a jazz-colored dominant resolution)
- G#maj7 – A#13 – D#maj7 (a ii-less turnaround using extended chords)
- Cm7 – A#13 – D# (a jazzier ii – V13 – I feel)
- D# – A#13 – D# (I – V13 – I as a static vamp with color)
FAQ
- Why does the guitar voicing of A#13 skip the ninth and eleventh?
- Fitting root, third, seventh, ninth, eleventh, and thirteenth across six strings isn't realistically playable, so the notes that most strongly define the dominant-with-color sound — root, third, seventh, and thirteenth — are kept, and the rest are dropped.
- How does A#13 relate to A#6?
- Both voicings put the sixth/thirteenth on top and share much of their fingering; A#13 keeps the flat seventh where A#6 has a plain triad tone, which is the difference that makes one dominant and the other stable.
- What does A#13 resolve to?
- Eb (D#) major, the same destination as A#7 or A#9, since it's still fundamentally a dominant seventh chord dressed up with extra top-end color.
- Is A#13 mainly a jazz chord?
- It's most at home in jazz and jazz-adjacent styles like bossa nova and swing, though it appears occasionally in more sophisticated soul and R&B writing built around flat keys.
- Why might A#13 get mistaken for A#6 at a glance?
- Both put G on top and share most of the shape; the flat seventh buried in the middle is the note that actually separates the two chords.
- Does A#13 need a ii chord before it to work?
- Not strictly — it resolves fine from a static vamp or the tonic itself, though following a ii chord like Cm7 gives it the classic ii-V jazz cadence feel the color is often written to support.
- How hard is A#13 compared to a plain A#/Bb barre?
- It asks for one or two extra fretted notes beyond the basic barre, comparable in demand to A#9, a reasonable next step once the plain sixth-fret barre feels solid.
- Would a capo help simplify A#13?
- Not particularly — the chord's color comes specifically from stacking a sixth-like note over a dominant seventh, and a capo doesn't reduce the finger independence that stacking requires, so the sixth-fret barre stays about as manageable as this chord gets.
- Does A#13 ever appear without the third present?
- Some players simplify it further by dropping the third as well, leaving essentially root, seventh, and thirteenth — a leaner, more open-sounding variant that trades a little harmonic completeness for ease of fretting.
- How should the thirteenth be balanced against the rest of the chord when strumming?
- It doesn't need to be picked out or emphasized on its own; letting the whole barre ring evenly is enough for the ear to register that lush, layered dominant color.
- Why does a thirteenth chord represent the practical top of extended harmony?
- Stacking any further would just double the root an octave up, so thirteen is effectively as far as tertian, third-based chord-building can go before the notes start repeating themselves.
- Are thirteenth chords associated with any particular instrument more than others?
- They're most idiomatic on piano and in horn arrangements, where every stacked tone can actually be voiced at once; guitar's reduced version is a practical compromise that still gestures at the same harmonic richness.
Related: how chords are built, chord finder.