HOW TO WORK OUT A 12 BAR BLUES IN ANY KEY
The most basic 12 bar Blues only uses three chords. For instance, in the key of C we use the chords C, F and G. If you go by the scale of C you will see that the three chords are built on the 1st, 4th and 5th notes of the scale (These chords are known as I, IV and V)
If we use this formula, we can figure out the three basic Blues chords of ANY key. Here is the standard Blues progressions for the easier keys.