B Sharp, E Sharp, C Flat and F Flat

c sharp mixolydian mode on treble clef

About once per month, we have a considerate visitor to our website write to inform us about typos in the list of notes on our scale list. The most popular scales that receive this attention are C# Mixolydian, F# Major, and F# Harmonic Minor because these scales contain an E#.  

Most people with a basic understanding of music know that the black keys on a piano are considered the “sharp” and “flat” keys. They also know that there are two pairs of white keys on a piano that do not have a black key in between them. These two pairs are B / C and E / F. 

So E#?  Isn’t that simply an F? Indeed, it is the same frequency.


So why would one write it as an E#?  

When properly writing scales, the same letter is never used twice.  For example, in the scale of C# Mixolydian, the scale is properly written with an E# and F#. For this reason, the “F” note is known as E#. The same is true in F# Major and F# Harmonic Minor, which both have a major 7th scale degree, known as E#.

In time, we will release a C# major scale with a B# and E# as well as a Eb minor scale with a Cb note 😉 

A great source that we regularly use for referencing scales is