How Key Signatures Work

Learn How Guitar Key Signatures Work!

This guitar lesson will teach you how to find out the key signature of a given key and how to tell what the sharps or flats in that key are.  It is probably best to just memorize your key signatures, but understanding this how key signatures work will go a long way in helping you to be a better musician. First we will look at the sharp keys and then we will move on to flat keys.


There are two sequences of notes, one for sharp keys and one for flat keys, that you can use in order to figure the key signature and number of sharps or flats for any given major key. For sharp keys the sequence is FCGDAEB and for flat keys the sequence is BEADGCF. The sequence FCGDAEB can be remembered by the phrase ”Father Charles Goes Down And Ends Battles”. That may seem a bit silly but it will help you to remember the names of those notes in the sequence. You can also think of what we call the cycle of 5ths in order to remember this series of notes. Start on the F and count up 5 notes to a C. Now count five notes from C to a G. If you keep counting up five notes every time you end up with FCGDAEB.


Since the key of C major has no sharps or flats we will use it as the starting point in the sequence. Look at the G note in the sequence. It is the next letter right after C. The key of G major will have one sharp. You could also say that the key signature for G is one sharp. Now look at the next letter in the sequence, it is a D. The key of D major will have two sharps. Continue down the sequence with this same idea and you will find that the key of A major has three sharps, E major has four sharps and so on.


Now we need to find out which sharps go with the key signatures we just found. Take the key of D major for an example. We found out that the key signature for D major is two sharps. Go back to the very beginning of the sequence FCGDAEB. The first letter is an F and the second is a C. Those are the two sharps in the key of D. Take this one step further with the key of A major. A major is the third note away from C in the sequence so the key signature would be three sharps. Those three sharps are F sharp, C sharp, and G sharp.


The sequence of notes for flat keys is BEADGCF. You can think of the word “BEAD” to remember the first four notes and “juicy fruit” to remember G C and F. I know juicy is spelled with a j not a g but it helps to remember the sequence. Look carefully at this sequence. BEADGCF is just FCGDAEB backwards. Instead of a cycle of 5ths, BEADGCF is a cycle of 4ths. Four notes away from B is E, four notes away from E is A and so on.


The sequence for flats works the exact way that the sequence for sharps does. Start on the C. Remember the key of C has no sharps and no flats. The next note over in the sequence is an F. The key of F major has one flat in it. Go all the way back to the beginning of the sequence to the B. That is the one flat in the key of F major. Start on the C again and go two notes over. F would be one and then you would go back to the beginning of the sequence to a B for the second note. This would be the key of B flat. Since B flat is two notes away from C in the sequence it will have two flats. Those two flats are B flat and E flat.


This is a lot of information to absorb in one lesson so don’t feel bad if you did not catch everything the first time through. Try to find out the key signatures for other major keys using the two sequences. Once you think you have the answer look it up on the Internet to see if you are right. Of course the best thing to do is just flat out memorize all of your key signatures.

Learn more about the theory of guitar, how chord extensions are made, and how key signatures work in these guitar lessons!

This Lesson Has 28 Comments

  • Rishav says:

    what is a key?

  • Dru says:

    Nate you make this so easy to understand.

  • Liza says:

    Wow!I had taken guitar lesson before (and even paid for them , ofcourse) but they never taught me this! Thanks!

  • Diesel McGunner says:

    I understand what you’re saying but I don’t really know why you need to know how many sharps and flats are in each major scale. In what way could you use this information so it is helpful?

  • Adam says:

    A great lesson as always! I was taught another way of learning the flats (BEADGCF). As you said, a good way of remembering the flats is Father Charles Goes Down And Ends Battle. You can use that for the flats and say Battle Ends And Down Goes Charles’ Father. Just thought I’d add that!

    • Chris says:

      Hi Adam,

      Just so others aren’t confused…I believe what you meant to say was “a good way of remembering the sharps is Father Charles Goes Down And Ends Battle.

      You accidentally said flats instead of sharps.

      Also, this is an excellent article! I’ve never understood the cycle of 5ths and 4ths until reading this. Why don’t all of those music theory books just explain it like this? The way it’s explained here, you don’t even need the illustration of the circle (which is mandatory in all music theory books) to understand to understand the cycle of 5ths. Thank you very much!

    • Karen says:

      Nice job but it gets a bit sloppy nreear to the end and it definitely needs music!!!! but nice vid though!!VA:F [1.9.11_1134]please wait…VA:F [1.9.11_1134](from 0 votes)

  • Dave S says:

    I am working on how to figure sharps and flats and am doing fairly well. I am a bit confused about one thing, I have the sharps figured for all but the key of “F”, how many sharps are there supposed to be? I went by the pattern FCGDAEB and everything matches but “F”. Thanks Nate, your lessons and your help is amazing, even have my son in law hooked on guitar now and he loves the sight!

    • Nate Savage says:

      Hi Dave,

      There are not any sharps in the key of F but there is one flat. That flat is a B flat. The F major scale is spelled FGABbCDEF.
      If you flip the FCGDAEB around you get BEADGCF. That is the sequence of notes that you need to memorize to figure out your keys that use flats. Start on C because C has no sharps or flats. Go to the next letter over which is an F. The key of F has one flat, B flat. Go to the next letter in the sequence to find out which key has 2 flats. The next letter is a B but in this case it will be the key of Bb. The key of Bb has 2 flats, Bb and Eb. Continue doing this for the keys of Eb, Ab and so on just like you did for your sharp keys. Sorry for the long answer but there it is.

    • Bryan says:

      i dont know if i am doing this right but there is a trick on the guitar that my oatfrive band Megadeth does its a twin sound that both guitarests play a certain note and playes a beautiful sound that sounds really good i wanted to know what that is and how to pull that off. And there is a guitar playing hammer on and pull off trick that mst guitarest do when playing solos down the neck where they pick really fast and hit notes on a lower string but the same fret (hope you understadn) well thanks

  • Dave S says:

    Thanks Nate, I know about the anacronyms but when I tried it with “F” it didn’t fit, now I know why. I don’t just want to play, one day I would love to write music also, thanks again for all your help.

  • Robert Johnson says:

    You are a rubber cock, Nate.

    • Richard says:

      Your ignorance is overwhelmed by your intelligence and amount of vocabulary! Gutter talk shows where your mind is “IN THE GUTTER”!

  • Joel says:

    Robert Johnson, your name sounds like Rubber Cock, what did you mean when you refered to nate as a “rubber cock”? Do you think your statement was appropriate, or are you just such a loser that you have nothing better to do?

  • Chad says:

    Fuck chad, god damn asshat, eat butts


  • Chad says:

    Seconding diesel mcgunner

    I can remember this, but why?

  • hannah says:

    um im 13 i will be taking lessons soon does that work for acoustic guitar

  • Trevor says:

    A better acronym is Fat Children Get Diabetes And Eat Badly

  • Quyen says:

    Thank you very much for your lesson.

  • Andrew says:

    Wow! I thought my head was going to explode trying to figure out which notes were sharps or flats. I just read it for the 4th time and got it.

  • Khaled says:

    How did you know the note names and located them on the fretboared that’s Confusing me and I need an answer Asap !!

  • Junior Sixdie Amituana says:

    I’ve learnd more on this lesson..thank you very much…:)
    if u wanna add me on ,you can find me as junior sixdie amituanai.

  • Atharva Mitragotri says:

    Dude you rock!!!!

  • kat says:

    Wow some of the people commenting on this sound so stupid it’s actually making my head hurt…. To the person who asked why sharps and flats are relevant, if you don’t know what the notes are in a key, how are you going to play that key? If you think its not important, just stick with C Major for everything…

  • kat says:

    And the person who asked what is a key? ……if you seriously don’t know what a key is, you should leave this thread and go take beginner music and learn notes, key signatures, and time signatures before you attempt to learn anything else…

    • Nate Savage says:

      If anyone needs to start with the basics of how keys work I would go through The Major Scale Masterclass here on


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