B♭ augmented major 7th chord on guitar (B♭augMaj7)

Also called or written B♭augMaj7, B♭augM7, B♭+M7, B♭M7#5, B♭maj+7, B♭ augmented major seventh or B♭ major seventh sharp five

B♭ augmented major 7th contains B♭, D, F♯, and A. The open D string rings between fretted notes on the A and G strings, creating a wide stretch.

B♭DADF♯EADGBE
Positions on the neck1 of 5
Practice B♭ augmented major 7th chord

How it is built

B♭RootDMajor thirdF♯Augmented fifthAMajor seventh

Formula 1, 3, ♯5, 7

Inversions

How do you play a B♭ augmented major 7th chord on guitar?

B♭ augmented major 7th is played in open position as × 1 0 2 3 2: index finger on the A string at fret 1, middle finger on the G string at fret 2, pinky finger on the B string at fret 3 and ring finger on the high e string at fret 2. The D string rings open. The low E string stays muted.

Full note and interval breakdown
StringFretFingerNote
6 (E)muted
5 (A)11B♭ (1)
4 (D)openD (3)
3 (G)22A (7)
2 (B)34D (3)
1 (e)23F♯ (♯5)

AdvancedThe pinky must reach the 3rd fret on the B string while the index finger holds the 1st fret on the A string, creating a wide stretch.

B♭augM7/D inversion

B♭ augmented major 7th is played at the 3rd fret as × 5 4 3 3 5: barre your index finger across fret 3, ring finger on the A string at fret 5, middle finger on the D string at fret 4 and pinky finger on the high e string at fret 5. The low E string stays muted.

Full note and interval breakdown
StringFretFingerNote
6 (E)muted
5 (A)53D (3)
4 (D)42F♯ (♯5)
3 (G)31 (barre)B♭ (1)
2 (B)31 (barre)D (3)
1 (e)54A (7)

B♭augM7/F♯ inversion · F♯ on top

B♭ augmented major 7th is played in open position as 2 0 0 3 3 2: index finger on the low E string at fret 2, ring finger on the G string at fret 3, pinky finger on the B string at fret 3 and middle finger on the high e string at fret 2. The A and D strings ring open.

Full note and interval breakdown
StringFretFingerNote
6 (E)21F♯ (♯5)
5 (A)openA (7)
4 (D)openD (3)
3 (G)33B♭ (1)
2 (B)34D (3)
1 (e)22F♯ (♯5)

B♭augM7/F♯ inversion · D on top

B♭ augmented major 7th is played in open position as 2 1 0 2 3 ×: middle finger on the low E string at fret 2, index finger on the A string at fret 1, ring finger on the G string at fret 2 and pinky finger on the B string at fret 3. The D string rings open. The high e string stays muted.

Full note and interval breakdown
StringFretFingerNote
6 (E)22F♯ (♯5)
5 (A)11B♭ (1)
4 (D)openD (3)
3 (G)23A (7)
2 (B)34D (3)
1 (e)muted

B♭augM7/F♯ inversion · A on top

B♭ augmented major 7th is played at the 3rd fret as × × 4 3 3 5: ring finger on the D string at fret 4, index finger on the G string at fret 3, middle finger on the B string at fret 3 and pinky finger on the high e string at fret 5. The low E and A strings stay muted.

Full note and interval breakdown
StringFretFingerNote
6 (E)muted
5 (A)muted
4 (D)43F♯ (♯5)
3 (G)31B♭ (1)
2 (B)32D (3)
1 (e)54A (7)

Why it sounds like that

B♭ augmented major 7th is built from the formula 1, 3, ♯5, 7. The augmented 5th, F♯, is what separates it from the B♭ major 7th, where the 5th is F natural. The major 3rd and major 7th remain unchanged.

What goes wrong with B♭ augmented major 7th?

  • Letting the low E string ring instead of muting it.
  • Fretting the B string with the ring finger instead of the pinky, causing the note to go flat.
  • Allowing the middle finger to touch the B string, muting the 3rd fret note.

When to use it

B♭ augmented major 7th works as a substitute for B♭ major 7th when the melody moves to the ♯5. It fits jazz ballads and passages that need a brighter, more restless major sound.

Changing to and from B♭ augmented major 7th

  • Sliding the shape down one fret to the 2nd fret gives A augmented major 7th.
  • Sliding the shape up one fret to the 4th fret gives B augmented major 7th.

Which voicing to use

The open voicing keeps B♭ in the bass and is easiest to reach. The D inversion starting on the 5th fret puts the major 3rd in the bass and gives a tighter, higher register.

Other B♭ chords

Common questions

How is B♭ augmented major 7th written?

B♭ augmented major 7th is written B♭+M7, M7#5, maj+7, or B♭augM7. The ASCII root is Bb. It is also spelled A♯ in enharmonic notation for the same sounding root.

What is the difference between B♭ augmented major 7th and B♭ augmented?

B♭ augmented major 7th adds the major 7th, A, to the B♭ augmented triad B♭–D–F♯. The 7th creates a leading tone back to B♭ major.

Why does the open E string get muted?

The open E string is muted because E is not a chord tone in B♭ augmented major 7th. Playing it would add an unintended 5th below the root.