How many major keys are there?

[Redsfan79]

Depending on which website you read, you'll see either 12 or 15. Which is it?

[c+t in b]

12 if you go by pitch. 15 if you go by key signature.

[Jed]

 

12 if you go by pitch. 15 if you go by key signature.

 

 

Of the major keys only:

Keys with Flats = F, Bb, Eb, Ab, Db, Gb, Cb = 7 keys with flats

Keys with Sharps = G, D, A, E, B, F#, C# = 7 keys with sharps

Keys with no sharps or flats = C = 1 key with no sharps or flats

 

So there are the fifteen major keys. But there are only 12 notes in the western music system, so how can there be 15 major keys ??

 

The way we name and describe notes and scales is an imperfect system that results in the following:

The key of B major (5 sharps) and the key of Cb major (7 flats) produce all of the same sounds but require different names for the notes and chords. These two keys are often described as "enharmonic" meaning notes / intervals / chords / scales that have different names but are the same pitch / frequency.

 

B is enharmonic to Cb

C# is enharmonic to Db

D# is enharmonic to Eb

E is enharmonic to Fb

F# is enharmonic to Gb

G# is enharmonic to Ab

A# is enharmonic to Bb

B is enharmonic to Cb

 

Likewise, the keys of F# major and Gb major are enharmonic-ly related.

Lastly, the keys of C# major and Db major are enharmonic-ly related.

 

So if you do not count both of the enharmonic-ly related key pairs (only count three of the six keys described above) - then you get to the count of 12 keys that people commonly refer to.

 

cheers,

[JonR]

Just to put all that another way :

 

There are 12 keys, but 3 of them have two names - the enharmonic ones: B/Cb, F#/Gb, Db/C#. That's how it makes 15.

 

The reason those ones have two names is that both names are useful at different times.

F# and Gb each have 6 altered notes (6 sharps or 6 flats) so neither is simpler than the other.

B (5 #s ) and Db (5 bs) would normally be chosen in preference to Cb or C#, but there are times when Cb or C# would be preferred.