Scale degrees · G major

The ♭3 of G is B♭

The ♭3 (flat three, written b3) of G is B♭ (B flat): a minor third above the root.

How to find it

Count letters first, the root included: G, A, B. A 3rd lands on B.

Then the sound: a minor third is 3 semitones above G, and the B that is 3 semitones up is B♭.

That is why it is B♭ and not A♯: A♯ is the same key on the piano, but from G it would be a 2nd, not a 3rd.

Where you meet it

The ♭3 makes a chord minor: G minor is the root, B♭ and the 5th. Over a dominant chord the same key on the piano is usually written as the ♯9, with another letter.

In G minor:

G · B♭ · D

The ♭3 in every key

Key	The ♭3
C	E♭
G	B♭
D	F
A	C
E	G
B	D
F♯	A
D♭	F♭
A♭	C♭
E♭	G♭
B♭	D♭
F	A♭

Every degree of G