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Key Signatures - An Introduction

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Key signatures can seem intimidating, but have no fear! Our beginner’s guide has all you need to get started.
Featured Image of Key Signatures - Shows a book of musical notation with a flower on top.

In this guide we’ll run through key signatures, what they are and why they’re used in music. Most importantly you’ll learn how to read and understand them, along with some expert tips to make learning them easier than ever! 

In This Guide
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    What is a Key Signature?

    A key signature is the combination of sharps and flats directly following the clef at the beginning of a stave. These sharps and flats affect all the subsequent notes on their line or space, dictating whether the note should be played as a flat or a sharp. Ultimately indicating which key the piece of music is written in. 

    Let’s take the key signature for D Major as an example:

    You can see in the image above there are sharps sitting on the lines of F and C. This means that any F or C notes in this piece of music should be played as F# and C#. 

    Equally, key signatures can also use flat notes. For example, the key of B♭ major has two flats B♭ and E♭. This would be written as:

    Why are Key Signatures Useful?

    Key signatures are useful on a number of levels. Primarily they make musical notation much easier to read, by reducing the number of accidentals needed. Secondly, a key signature gives a clear indication of which key the piece of music is written in. Making it much easier for musicians to play, interpret and even improvise over the piece of music. 

    How to Read Key Signatures

    Although key signatures seem challenging to understand, they are easy once you get into them. One of the best and most common guides to understanding key signatures is The Circle of Fifths. Knowing The Circle of Fifths also comes in handy when doing more advanced techniques in music theory, such as transposition.

    As you can see in the image above, the 12 chromatic scale notes are listed around the circle with their corresponding key signatures.


    • The outer edge of the circle shows the key signature.
    • The capital letters show the major key that matches the key signature next to it.
    • The lowercase letters show the relative minor key.

    To understand better, let’s use C Major Scale as an example. Looking at the circle, you see that C Major has no sharps or flats, and its relative minor is A minor.

    There are also rules to key signatures which makes understanding them and The Circle of Fifths much easier.



    • Key signatures will have either sharps or flats but never both.
    • There is only one major scale, and one relative minor for every key signature.
    • The most sharps or flats you will ever have in a key signature is seven.
    • Sharps and flats fall in a specific order, which never changes.
    • In key signatures, the sharps and flats are always written on specific notes on the staff.

    Sharp Key Signatures

    In musical notation, sharps raise the note a half step. The symbol for a sharp is #, and as mentioned above, the order of sharps never changes. 

    As you can see, the first sharp is always F#, followed by C#, G#, D#, A#, E#, and B#. 

    An easy way to remember the order of sharps is the mnemonic Father Charles Goes Down And Ends Battle.

    Each scale, other than C Major, has sharps or flats. The following is a list of all the major scales and their relative minors with sharps.

    G Major / E Minor – 1 sharp, F#

    D Major / B Minor – 2 sharps, F# and C#

    A Major / F# Minor – 3 sharps, F#, C#, and G#

    E Major / C# Minor – 4 sharps, F#, C#, G#, and D#

    B Major / G# Minor – 5 sharps, F#, C#, G#, D#, and A#

    F# Major / D# Minor – 6 sharps, F#, C#, G#, D#, A#, and E#

    C# Major / A# Minor – 7 sharps, F#, C#, G#, D#, A#, E#, and B#


    Flat Key Signatures

    Flats are the opposite of sharps because they lower the note a half step. The symbol for a flat note is b, and the order of flats also never changes.

    The first flat is always Bb, followed by Eb, Ab, Db, Gb, Cb, and Fb.

    The mnemonic to aid in remembering the order of flats is Battle Ends And Down Goes Charles’ Father.

    The list of the major scales and their relative minors is: 

    • F Major / D Minor – 1 flat, Bb
    • Bb Major / G Minor – 2 flats, Bb and Eb
    • Eb Major / C Minor – 3 flats, Bb, Eb, and Ab
    • Ab Major / F Minor – 4 flats, Bb, Eb, Ab, and Db
    • Db Major / Bb Minor – 5 flats, Bb, Eb, Ab, Db, and Gb
    • Gb Major / Eb Minor – 6 flats, Bb, Eb, Ab, Db, Gb, and Cb
    • Cb Major / Ab Minor – 7 flats, Bb, Eb, Ab, Db, Gb, Cb, and Fb

    Key Signature Chart

    The following is a chart of all the different key signatures.

    Tips to Help You Remember Key Signatures

    Learning key signatures can be overwhelming, and as a beginner, it’s easy to get them mixed up. Luckily, there are a few hacks worth remembering to help simplify the process.

    Major Keys

    • Major Sharp Keys – To easily determine the key of a major key with sharps, look at the last sharp in the key signature and go up a half step.
        • For example, the last sharp in E Major is D#. So a half step up from D# is E. 
    • Major Flat Keys – To quickly determine the key of a major key with flats, look at the second to last flat, and that will tell you all you need to know.
        • For example, Ab Major is constructed of Bb, Eb, Ab, and Db. As the second to last flat in Ab major is Ab.

    Minor Keys

    The easiest way to learn the minor keys is by memorizing the major keys and The Circle of Fifths. Once you know that, take the major key and drop it down a minor third. A minor third isn’t as complex as it sounds. Think of a minor third as three half steps.

    • For example, three-half steps down from E is C#. So, the relative minor of E Major is C# minor.

    Understanding key signatures is a crucial fundamental in musical theory. Although they may seem intimidating at first, understanding the relationships between them and the patterns in their construction will have you well on your way to mastering them in no time!  

    Alex Martin
    Alex is a professional musician, with a BSc from Leeds Becketts University in Creative Music & Sound Design Technology.