Flat key signatures cover seven of the twelve major keys: F, B♭, E♭, A♭, D♭, G♭, and C♭ major. Each one adds one more flat to the staff in a fixed order, and learning that order is the fastest way to recognize any flat key signature at a glance.
This is part 3 of our key signatures series. Part 1 covers the basics, and part 2 covers sharp major keys. This guide lists every flat major key signature, shows it on the staff, and explains the trick to identify any flat key from its signature.
Major key signatures with flats
The seven major keys that use flats are F, B♭, E♭, A♭, D♭, G♭, and C♭ major. Each adds one flat to the previous key, following a fixed sequence: B♭, E♭, A♭, D♭, G♭, C♭, F♭. The order is the exact reverse of the order of sharps.
F major key signature (1 flat)
F major has one flat: B♭. The key signature appears at the start of each line of music, telling you to play B as B♭ throughout the piece.
In the score below, the first two bars show the F major scale written with no key signature (every B is explicitly flat). The next two bars use the proper F major key signature — once you set the key signature, you don't need to write the ♭ on every B.
B♭ major key signature (2 flats)
B♭ major has two flats: B♭ and E♭. It's one of the most common keys in concert band and jazz repertoire because many wind instruments are pitched in B♭.
E♭ major key signature (3 flats)
E♭ major has three flats: B♭, E♭, and A♭. Another favorite for brass and big band writing.
A♭ major key signature (4 flats)
A♭ major has four flats: B♭, E♭, A♭, and D♭. Common in romantic piano repertoire (Chopin used it extensively).
D♭ major key signature (5 flats)
D♭ major has five flats: B♭, E♭, A♭, D♭, and G♭.
G♭ major key signature (6 flats)
G♭ major has six flats: B♭, E♭, A♭, D♭, G♭, and C♭. The enharmonic equivalent of F♯ major (6 sharps) — they sound identical but are written differently.
C♭ major key signature (7 flats)
C♭ major has all seven flats: B♭, E♭, A♭, D♭, G♭, C♭, and F♭. F♭ is technically the same pitch as E natural, but in this key it's written as F♭ to keep one note of each letter name. C♭ major is rare and is usually written enharmonically as B major (5 sharps) for easier reading.
How to memorize flat key signatures
The flats always appear in the same order on the staff, no matter the key: B♭, E♭, A♭, D♭, G♭, C♭, F♭. A common mnemonic is "Battle Ends And Down Goes Charles' Father" — the exact reverse of the order of sharps.
Finding the key from the signature
For flat key signatures, the trick is different from sharps. If there's only one flat (B♭), the key is F major — there's no shortcut for this one, just memorize it.
For two or more flats, look at the second-to-last flat. That tells you the key. If the last two flats are B♭ and E♭, the second-to-last is B♭ — and the key is B♭ major. If the flats are B♭, E♭, A♭, D♭, G♭ (5 flats), the second-to-last is D♭ — and the key is D♭ major.
Finding the signature from the key
If you know the key and need to write the signature, count up from F: F (1 flat), B♭ (2), E♭ (3), A♭ (4), D♭ (5), G♭ (6), C♭ (7). Or memorize the major scales — once you know A♭ major is spelled A♭, B♭, C, D♭, E♭, F, G, A♭, you can count the flats directly (4 in this case).
Practice flat key signatures
The fastest way to internalize key signatures is to write scales in them. Open Flat, start a new score in each flat key, write the major scale, and hear it played back. After a few rounds, recognizing flat key signatures at a glance becomes automatic.
Key signatures series
- Part 1: Introduction to key signatures
- Part 2: Major key signatures with sharps
- Part 3: Major key signatures with flats
- Part 4: Minor key signatures