Learn Key Signatures

Weekly Newsletter #8

September 30, 2021

One important thing that sets a performing guitarist apart from your average bedroom player is knowing your keys. I don’t mean keyboards, I mean knowing what it means when somebody says “Hey, let’s jam in Bb”. 

If you are unfamiliar with key signatures and how to know instantly what notes are in every key, then this will likely be a game-changer. 

Firstly, its incredibly important to know your key signatures because let’s face it, you can’t just play a minor pentatonic scale over everything. It is much more musical to know the notes in a key and have the freedom to choose the ones you want, instead of being stuck in the same boring pentatonic box. 

Before we get to that, it’s important to understand that there are essentially 3 types of keys: Sharp keys, Flat keys and the key of C major. 

Now C major is the easiest of all keys because it has only natural notes: 

C D E F G A B C 

Sharp keys are those that have a mixture of sharps and natural notes, while flat keys are those that have a mixture of flats and natural notes. Take a look at one of the most important tools for any musician, the Circle of Fifths. 



This may seem confusing but we will break down all the info so you can truly understand it. 

On the outside of the circle in red, you have the names of the major keys, all 12 of them, and next to each you have their corresponding key signatures written in musical notation. 

 At 12 O’clock we have the key of C major, once again there are no sharps or flats and so there is no musical notation for this key. But look at the key of G, there is a music staff with a treble clef and one sharp. This is the key signature for G major (we’ll get to what it means and how to remember it). 

Next, in the grey circle we have the number of accidentals in each key (accidentals are a way of saying ‘any note that isn’t a natural note’…it means sharps or flats). In the key of G, with one sharp, you see: “1#” in the grey circle. 

On the inside circle, in green writing we have the relative minor for each key. Every major key has a related minor key that shares the exact same set of notes. For example, the relative minor of G is E minor. 

As you can see, the sharp keys are on the right of the circle while flat keys are on the left. Going clockwise from 12 O’clock to 6 O’clock on the circle each keys gets one sharp more than the previous key. G has one sharp, D has 2 sharps, A has 3 etc. The same is true for the flat keys. 

What this means is that each new accidental gets added on to the other accidentals that already exist prior to whatever key you’re working with. To illustrate this we will discuss sharp keys first. 

Sharp Keys 

As mentioned each new sharp that gets added as you go clockwise around the circle is added to any pre-existing sharp that came before it. For example in G major there is one sharp, it’s an F#. The next key, D major, has two sharps: F# and C#. This process continues until all sharps have been added. 

The order of sharps can be easily memorized with this mnemonic: 

Fat                  F# 

Cats                C# 

Get                  G# 

Drunk              D# 

At                    A# 

Ernie’s             E# 

Bar                  B# 

Every time you add a sharp you must have any prior sharps that existed before it. So that means a key with 4 sharps must have F#, C#,G# & D#. They can never be in any other order, and therefore you can’t have a key that has a C# but no F#. 

Now, the way you figure out your keys is pretty easy. If somebody says, “let’s play a song in E major” you simply take the note E and, in your head, go down ½ step to D#. That is going to be the last sharp in that key. So you say your mnemonic until you get to that letter: Fat Cats Get Drunk (F# C# G# D#). All the other notes are natural notes giving you the E major scale: E F# G# A B C# D# 

This process works for every sharp key. Test it out. Try B major. B goes down ½ step to A# which gives you 5 sharps: Fat Cats Get Drunk At (F# C# G# D# A#). 

One thing you might have noticed is that the last two sharps in the mnemonic are E# and B#. How is that possible? There is no E# or B#. Well the answer is that each key must have every letter represented once and only once. You can’t, for example have an F and an F# in a key. This means that in the key of C# major (which has all notes sharped) you would have C# D# E# F# G# A# B#. If you called that E# an F then you would have two F’s in the key, one natural and one sharp. The same goes for B#. 

However, if you look at the key of C# major on the Circle of Fifths, you’ll notice it can also be called Db major. Now count how many accidentals are in Db major and how many are in C# major. Db has 5 flats while C# has 7 sharps. This makes thinking about this key as Db much simpler because you have fewer accidentals to deal with. 

Now, on to flat keys: 

Flat Keys 

Flat keys follow the same rule as sharp keys, in that each one is added to all previously existing flats. You can’t have the 3rd flat without also having the first two. 

As for the order of flats, it is the reverse order of sharps: 

Battle              Bb 

Ends               Eb 

And                 Ab 

Down              Db 

Goes               Gb 

Charles           Cb 

Father              Fb 

Just as sharp keys have the strange names E# and B#, flat keys have Cb and Fb for the same reason. You can only have each letter once in a key and they must all be present. 

The difference with flat keys is how you remember the notes in each key. Unlike sharp keys where you take the name of the key and go down ½ step to find the last sharp in line, with flat keys, the second to last flat is the name of the key itself. This means that a key signature with 3 flats: Bb Eb & Ab is called Eb major. All the other flat keys are just as simple. 

The only exception is the key that has only one flat: F major. Since there is no ‘second to last flat’ you simply have to remember that F major has one flat. You can always remember the flats by saying the mnemonic. 

Essentially, remembering the notes in every key can be boiled down to a process: 

Is the key a flat key, sharp key or natural key? If natural then it can only be C major. If flat it will almost certainly have a flat in the name of the key (except for F). All the other keys are sharp keys. 

If it’s a sharp key, take the name of the key and think ½ step lower than that. This new note will be the last letter in the mnemonic for sharps. 

Key of A: down ½ step = G#. Fat Cats Get. The key of A has 3 sharps: F# C# G#. All the other notes are natural. A B C# D E F# G# 

If it is a flat key, then simply remember that the name of the key is the second to last flat. Say the mnemonic for flats until you get to the letter of that key and then add just one more from the mnemonic. 

Key of Ab: Battle Ends And Down. The key of Ab has 4 flats: Bb Eb Ab Db, all the other notes are natural. Ab Bb C Db Eb F G 

I hope that you can now rest easy knowing that any time somebody asks you to play in any key, you can comfortably say “Rock On!” 

If you have any questions or are interested in private lessons please feel free to contact me at max@maxrichmusic.com 

Keep on shredding! 

Max Rich