The blues scale is a six-note scale built from the minor pentatonic scale plus one extra note, the flat 5th, called the blue note. A blues is A, C, D, Eb, E and G, spelled A, C, D, D#, E, G, and the blue note gives the scale its tense, soulful sound.
What is the blues scale?
The blues scale is a six-note scale built from the minor pentatonic scale plus one extra note, the flat 5th, called the blue note. A blues is A, C, D, Eb, E and G, spelled A, C, D, D#, E, G in the sharp-only system used by ChordFlow. The interval pattern is 0, 3, 5, 6, 7, 10 semitones above the root, and the blue note, the note six semitones above the root, is what gives the scale its tense, soulful, crying sound. The blues scale is the sound of the blues, and it has shaped rock, jazz, soul and pop for more than a century. It is a minor pentatonic scale with a single added note, but that note changes everything: the flat 5th sits exactly halfway between the root and the octave, a tritone away, and it creates a tension that the ear hears as soulful and expressive, rather than wrong. Blues players bend into the blue note, slide through it, and use it as a passing colour, never landing on it for long, because its power comes from its instability.
How the blues scale works
The blues scale is built by taking the minor pentatonic scale, 0, 3, 5, 7, 10, and adding the note six semitones above the root, the flat 5th. In A minor pentatonic, A, C, D, E, G, the added note is Eb, which sits between D and E, so the blues scale is A, C, D, Eb, E, G. The blue note is a tritone above the root, and it is the most dissonant note in the scale, which is why blues players treat it as a passing note: they touch it briefly and move on, rather than holding it. The blues scale is used over dominant 7th chords, which is what makes the blues work: the minor pentatonic scale clashes with the major 3rd of the dominant chord, and that clash is the blues sound. In a 12-bar blues in A, the chords are A7, D7 and E7, all dominant 7th chords with major 3rds, and the A blues scale, with its minor 3rd, C, plays against those major 3rds to create the tension that defines the genre. The A blues scale shows the notes, the 12-bar blues progression in A major shows the chords it is played over, and the scale finder builds a blues scale from any root.
Worked example — E blues. Take the E minor pentatonic scale, E, G, A, B, D, and add the flat 5th, Bb, spelled A#, which sits six semitones above E. The E blues scale is E, G, A, A#, B, D. On guitar the E blues scale is one of the most useful shapes to learn, because it fits over the E7, A7 and B7 chords of a 12-bar blues in E. Play the scale ascending and listen for the blue note, A#, sitting between A and B, and notice how it pulls your ear in both directions at once. The E7 guitar chord is the tonic chord of the blues it belongs to.
How to practise the blues scale
Practise the blues scale as a minor pentatonic scale with one extra colour, not as a new scale, so the blue note stays a spice rather than the main ingredient.
- Play the A minor pentatonic scale ascending, then add the blue note, Eb, between D and E, and listen for the tension it adds.
- Improvise over an A7 chord using the A blues scale, and use the blue note as a passing note, touching it briefly and moving on.
- Play the 12-bar blues progression in A major and play the A blues scale over all three chords, noticing that the same scale fits each one.
- On guitar, learn the blues scale shape in one position, then bend the blue note up toward the 5th, which is the classic blues technique.
- Use the scale finder to find the blues scale for the key you are playing in, and check that its blue note is the flat 5th of the root.
Common mistakes
- Landing on the blue note — The blue note is a passing note, not a resting note. Landing on it and holding it sounds wrong, because it is a tritone above the root. Touch it briefly and move on to a stable note.
- Playing the blues scale over a major 7th chord — The blues scale clashes with the major 7th of a maj7 chord, because the scale's minor 3rd and flat 5th fight the chord's major 7th. The blues scale belongs over dominant 7th chords, not major 7th chords.
- Forgetting the minor pentatonic underneath — The blues scale is the minor pentatonic scale plus one note, so if you cannot play the minor pentatonic scale confidently, the blues scale will not help you. Learn the pentatonic first, then add the blue note.
Quick reference
This table lists the blues scale in six keys, with the blue note in the last column so you can see the single note that is added to the minor pentatonic scale in each row. The blue note is always the flat 5th of the root, six semitones up, and it sits between the 4th and 5th degrees of the scale.
| Key | Blues scale notes | Blue note |
|---|---|---|
| A blues | A – C – D – D# – E – G | D# |
| E blues | E – G – A – A# – B – D | A# |
| D blues | D – F – G – G# – A – C | G# |
| G blues | G – A# – C – C# – D – F | C# |
| C blues | C – D# – F – F# – G – A# | F# |
| B blues | B – D – E – F – F# – A | F |
Work through the table by taking the minor pentatonic scale on each root and adding the flat 5th, checking your answers against the rows. When you can build all six without looking, play each blues scale over the dominant 7th chord of its key, and use the blue note as a passing note, touching it briefly and moving on.
Frequently asked questions
What notes are in the A blues scale?
A, C, D, Eb, E and G, spelled A, C, D, D#, E, G. They are the A minor pentatonic scale, A, C, D, E, G, plus the blue note, Eb, which sits six semitones above the root.
What is the blue note?
The flat 5th, the note six semitones above the root, which is added to the minor pentatonic scale to make the blues scale. In A blues the blue note is Eb, and it is the most tense note in the scale, which is why it is used as a passing note.
Why does the blues scale sound so soulful?
Because it combines the dark minor 3rd of the minor pentatonic scale with the tense flat 5th of the blue note, and because it is played over dominant 7th chords, whose major 3rds clash with the scale's minor 3rd. That clash is the blues sound.
Can I use the blues scale over major chords?
Yes, over dominant 7th chords, which are major triads with a minor 7th. The blues scale does not work well over major 7th chords, because the major 7th clashes with the scale's minor 3rd and flat 5th.
How is the blues scale different from the minor pentatonic?
One note: the blue note, the flat 5th. The minor pentatonic scale has five notes and the blues scale has six, and the extra note is what gives the blues scale its distinctive tension and its name.