What Is the Blues Scale?

That wailing, crying note that slips out of a guitar solo — the source of all that grit is the blues scale, and one note inside it called the blue note. Using A as the example (familiar to guitarists), the blues scale is six notes: A C D Eb E G. It is simply the minor pentatonic that so many guitarists already have under their fingers (A C D E G), with one note added: Eb. That added Eb — the b5, a flatted fifth — is the blue note that gives the blues its sound.

Hear it first

It is faster to feel this than to read about it. Use the player above: hear the minor pentatonic (A C D E G) first, then the blues scale with the blue note added (A C D Eb E G). As Eb passes through the gap between D and E, a sudden grittier, smeared quality appears.

You can also check it in the Scale Dictionary.

1. Open the Scale Dictionary
2. Set the root to A and the scale to “minor pentatonic”
3. Trace the keyboard and learn the five notes (A C D E G)
4. Switch to “blues scale” on the same root and hear the added Eb sitting in the gap between D and E

How the scale works

The quickest way to remember the blues scale is as the minor pentatonic plus one note.

• Minor pentatonic: A C D E G (degrees 1, b3, 4, 5, b7)
• The added note: the blue note Eb (b5, a flatted fifth)
• The result: A C D Eb E G (1, b3, 4, b5, 5, b7)

The key is that Eb sits right between the 4th (D) and the 5th (E). That tightly packed cluster of three half-step neighbors — D, Eb, E — is what creates the slippery, dragging sound the blues scale is known for.

The blue note was a pitch “between the keys”

This is the most interesting part of the scale. The blue note was never a note that fit neatly on a piano keyboard. The blues grew out of singing and string bends, and the blue note was a pitch sung or played between two notes — for example, a little lower than E but higher than Eb, slid into with the voice or a guitar (see Blue note on Wikipedia).

In other words, the b5 (Eb) written in scores and apps is really an approximation, on fixed pitches, of a bent, in-between tone (see Blues scale on Wikipedia). So in practice, rather than landing on Eb as a destination, use it as a passing note. Touch it briefly on the way up from D to E, or on the way down from E to D. On guitar, bending slightly from Eb up toward E is exactly where that “cry” comes from.

Where you hear it

True to its name, the blues scale is the foundation of the blues, but it is just as essential in the rock, jazz, and R&B that grew out of it. The wailing line in a guitar solo, a rock riff, that “wrong but right” note in a jazz improvisation — it is usually this blue note. Whether the underlying chord is major or minor, playing the blues scale in the melody on top instantly brings a bluesy air.

For composing: a fast way to add grit

When you want an original solo or riff to sound a little grittier, the blue note is one of the shortest routes.

• Think of it as adding just one note — Eb (the b5) — to the minor pentatonic you already use
• Do not hold Eb; pass through it quickly (a move like D to Eb to E feels natural)
• The backing chords can stay as they are. Just weave the blue note into the melody to instantly color the line

For listening: hearing the blue note

A solo that strikes you as “gritty” or “crying” usually has a blue note hiding in it. Listen for a move that steps a half step outside, between the 4th and 5th, and snaps right back — that brief smear. A guitar bend in particular is exactly the technique for singing that in-between pitch like a voice. Once you can hear that wobble that does not settle onto a fixed pitch, music rooted in the blues opens up.

What to try next

Picture a guitar solo or blues lick you know and hunt for the one note that feels “wrong but good.” It is very likely the blue note. Then play the “minor pentatonic” and the “blues scale” on the same root A in the Scale Dictionary and compare how much changes from adding only Eb. Scales get their character not just from the “right” notes but from one note you bend deliberately outside.

→ Play the blues scale in the Scale Dictionary