# Blues E scale on guitar

I am currently learning the guitar, particularly solo-ing, and teaching myself by figuring out the Blues scale in various keys. At the moment I'm looking at the key of E.

The way I understand it (may be incorrect) the Blues scale is based on this formula:

`1 b3 4 b5 5 b7`

That should mean the Blues scale in key of E becomes:

`E Gb A Bb B Db`

However, in a lot of places, not the least being the very highly-rated Guitarist's Reference app on Android, the scale is said to be:

`E G A Bb B D`

Being a newbie I'm struggling to find the reasoning behind this, and how it applies to other keys. Any pointers would be greatly appreciated.

Thanks.

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That notation (`1 b3 4 b5 5 b7`) is used to relate a scale to the major (ionian) scale. It shows which scale degrees should be flattened or sharpened (and by how much) relative to the major scale.
So, you should start with E major scale, not E minor or E phrygian (natural notes from E to E: `E F G A B C D`). E major scale is of course `1=E 2=F# 3=G# 4=A 5=B 6=C# 7=D#`. Because these are the notes that the famous `W W H W W W H` (W=whole, H=half, two frets and one fret on guitar respectively) formula produces when you start with E.
If you apply the formula `1 b3 4 b5 5 b7`, you end up with `E G A Bb B D`, which is what you found. Because the flats in b3 and b7 cancels the sharps of G# and D#.