Scale Theory: Part 2

Scale Construction – Part 2 Key Signatures

Key Signatures are like the “scale theory shortcut” … invented a long time ago by (probably) European classical musicians, you can find how to use them on this page. If you don’t read music (“notes” on the staff) and if you’ve never encountered any music theory in the past, this is a good place to start. Go slow, read on and don’t be afraid to ask questions!

In the course of this scale theory article series about scale construction, you’ll find music theory info about the major scale, how to read key signatures, modes and more…

Ready? Go!

Jump to a page:

Scale Construction 1: The Formula
Scale Construction 2: Building All the Keys [You’re Here]
Scale Construction 3: Intro to Modes
Scale Construction 4: 21 Most Common Modes


Scale Theory: Key Signature Introduction

As we said last time: every major key is unique. It means that any given major scale carries its own signature. That is, the amount of flats or sharps. The same signature is NOT duplicate, never.

So, the “key you are in” can be uniquely determined by what notes are altered. If I tell you “one sharp”, you can immediately take for granted that we’re in G major. If I say “one flat”, it’s F major. In terms of seeing this stuff on the staff, here’s how it looks like:

Key Signatures: Scale Theory

Key Signatures: G major (one sharp) and F major (one flat)

Simply put, the key signature (or we say “what’s at the clef”) is a way to summarize in what key a piece is to be played. In a single glimpse at the beginning of the score, knowledgeable musicians know immediately in what key they’re about to play.

Also: the sharps or flats in the key signature are “carried” throughout the piece unless they’re cancelled by a natural sign.

key signatures in G major and F majorCarried Sharp: in G major … see an “F natural” near the end.


Because, instead of writing a “sharp” besides every F note on a score for a piece that’s in G major, you simply have to write it once at the beginning and you’re done! Thank European classical composers for that. (-:

Scale Theory: ALL key Signatures

So, how many key signatures can their be? Well, as many as it takes to find all major keys! (-:

If you think about it, you can only have a maximum of 7 sharps or 7 flats for any given key. Any major scale has seven notes, and each note can only be altered once. That’s a total of 14 possibilities. If we count the key of C major (no flats / no sharps), we have a total of 15 different key signatures for major keys.

Of course, we have some repetitions, called enharmonic tonalities (same sound, appears different on paper) For instance: Cb=B, C#=Db, F#=Gb. Without those doubling we would of course only have our 12 keys from the western civilization musical system.

So, how can we find ALL the keys (and say, memorize what key has 3 flats, what key has 5 sharps, and so on)? I believe the best solution is…

  1. To truly understand where the key signatures are coming from (you should be pretty close by now!)
  2. To know *in what order* the alterations appear on the staff.
  3. And finally to build, memorize and practice common keys (up to 4-5 alterations) and the rest will take care of itself.

Scale Theory: Key Signature Order

The key signatures for all the major scale obey the rule of “gravity” regarding notes… You can start in any major tonality and if you move towards a new key, the INTERVAL in which you jump will determine the signature of the following key.

As a rule of thumb of scale theory, key signatures are added / subtracted one by one in cycles of fourths and cycle of fifths. (All the previous flats/sharps remain, but we add ONE following). It’s much easier to stick to that “move” and add or remove the alterations one by one. So…

  • Moving UP a fourth adds a flat or removes a sharp, and
  • Moving DOWN a fifth does the same thing.
  • Moving DOWN a fourth removes a flat or adds a sharp, and
  • Moving UP a fifth does the same thing.


Please note: Going down a fourth is the same as going up a fifth. For instance, C to G.
Going down a fifth is the same thing as going up a fourth. For instance, C to F.

key signatures with more flatsMoving Through Keys:
Up a fourth (or down a fifth) ADDS a flat.

key signatures with more sharpsMoving Through Keys:
Up a fifth (or down a fourth) ADDS a sharp.

Also, another “big thing”, is that the flats actually appear in the order of the ascending cycle of fourths… the first flat is “Bb”, the second is “Eb”, the third is “Ab”, etc. continuing in this manner. Same applies to sharps but in descending cycle of fourths order. That systematic scale theory!

So, from that point, it becomes pretty obvious hold to build all the 15 availables major key signatures… Simply start with G major (one sharp) or F major (one flat) and go “all the way through”. You can always go back to the formula WWHWWWH but it will take you forever! (-:

Sharps and Flats in “Table Format”

Order of Flat keys:
0: C major
1: F major
2: Bb major
3: Eb major
4: Ab major
5: Db major
6: Gb major
7: Cb major
This was “up a fourth”


Order of Sharp keys:
0: C major
1: G major
2: D major
3: A major
4: E major
5: B major
6: F# major
7: B major
This was “up a fifth”

Once you understand this well, it becomes easy to build “the full circle” and see all the 15 major signatures in one table (or picture) of scale theory. I’ve used ascending fourth cycle, but you could also use ascending fifths.

Order Key Signatures (both flats and sharps):
0: C major
1 flat: F major
2 flats: Bb major
3 flats: Eb major
4 flats: Ab major
5 flats: Db major … OR … 7 sharps: C# major
6 flats: Gb major … OR … 6 sharps: F# major
7 flats: Cb major … OR … 5 sharps: B major
4 sharps: E major
3 sharps: A major
2 sharps: D major
1 sharp: G major
0: C major
This was “up a fourth”

key signatures with more sharpsMoving Through Keys:
Circle in both direction.

Key Signatures in Minor

This is very easy. If you know your major scale key signatures well enough, simply rely on the relative minor-major principle:

  • In a major key, the relative minor lives on degree VI. For instance, C major scale has the relative minor of A minor scale.
  • In a minor key, the relative major lives on degree bIII. For instance, C minor scale has the relative major of Eb major scale.

Both relatives have the same key signatures.
C major and A minor have no alterations.
Eb major and C minor have three flats and so on…

So, simply keep in mind that whenever we see key signatures, they might imply a minor scale (say the piece is in a minor key) OR a major scale. The tunes in a minor tonality may have more accidentals written out throughout the piece if they utilize part of melodic minor or harmonic minor, in which case some degree are raised for the scale theory to work, for instance:

A minor piece has three flats so it’s…
C minor (natural) has three flats: C D Eb F G Ab Bb C
Same notes as in Eb major (they’re relative)

If the whole tune, or part of the tune has those scales:
C melodic minor: C D Eb F G A B C — A and B notes are natural
C harmonic minor: C D Eb F G Ab B C — B note is natural

…then some “accidentals” (alterations during the piece) will be required to supplement to information found in the key signature.


Scale Theory: One last *Trick*

One of the best advice about memorizing key signatures: learn up to four sharps and four flats and then use a little shortcut for more complicated key… this means, first memorize flat keys in this order: C, F, Bb, Eb, Ab and sharp keys in this order: C, G, D, A, E. (This is from zero to four alterations).

THEN, when a key signature has 5, 6 or even 7 alterations, think of the “opposed” key with the same amount of natural notes.

Let’s use an example: you see 6 sharps at the clef. It means that there’s only one natural note. Simply think of the key that has ONE flat… that’s it’s sibling. So, you deduce that 6 sharps means F# major … and the little brother is F major!

Same thing: you see 5 flats at the clef. There’s two natural notes. Think of the key with 2 sharps. So you deduce that five flats is Db major and the little brother (with 2 sharps) is D major.

In fact, if we were to compare the keys of F# and F, we would notice that all the sharp notes in F# become natural notes in F … and all the natural notes in F# become flat notes in F … etc. (rethink of the same process for yourself with a flat key, say Gb major). Complicated keys? Now easy peasy scale theory!

Scale Theory: So what else?

That’s it, you’re done! If you know this, you’re set for life, because everything else in scale theory (modes, symmetrical scales, improvisation, harmony, etc.) actually comes from this idea of WWHWWWH formula and key signatures.

This knowledge of key signatures is important, but please keep in mind, the more chromatic the music becomes (out-of-the-key) the less the signature is useful… Some “modern” (from recent years) jazz is written without key signatures because of its complexity. In this case, all alterations are accidentals, note-by-note. No scale theory needed. (-:

In the next installment of this scale theory series, we’ll discuss a subject matter that seems to confuse everybody … modes!

Jump to a page:

Scale Construction 1: The Formula
Scale Construction 2: Building All the Keys [You’re Here]
Scale Construction 3: Intro to Modes
Scale Construction 4: 21 Most Common Modes

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