What is the blues scale?
The blues scale is a set of six notes that gives blues, rock, and jazz solos their sound. Five of them are the minor ; the sixth — the , or '' — is the one note that turns the pentatonic into the blues scale. Counted from the , the six are 1, ♭3, 4, ♭5, 5, ♭7.
The blues scale grew out of the African-American spirituals, work songs, and field hollers of the 19th-century southern United States — music that carried older West African traditions of bent pitch and . Its 'blue notes' — the lowered third, fifth, and seventh — freeze those vocal pitches into keys you can play, and they carried the sound onward into jazz, R&B, and rock.
This page is a lesson, not a poster. Read it top to bottom; every section has something to press, and the whole page follows one root and one octave — change either and everything below changes with it. If the low keys are hard to hear on your speaker, use Octave + to lift the whole lesson.
1. First: what a scale is
A piano has only twelve different notes. After twelve keys the names start over — seven white (C D E F G A B) and five black — so a keyboard is the same twelve-note pattern repeated at higher and higher pitch. A is a short list of those twelve that a piece of music treats as home. Play only the notes on the list and everything sounds like it belongs together; the notes left off the list sound “outside” when they turn up.
The keyboard below is locked to A blues. Keys with a green number are on the list and play; keys with a red dot are off the list and stay silent. Press a few. Then press Play to hear the whole list in order, low to high and back. Tick Unlock other notes and the silent keys wake up — press one right next to a green key and hear how it sits outside the scale.
2. Counting from home: scale degrees
Every scale has one note that feels like home: the . The page opened on A; the root is now A, and the picker above moves it. Musicians name the other notes by how far above the root they sit — those names are . The easiest way to find one is to count keys to the right of the root, black and white alike. Each move from one key to the very next key is called a , so “six keys up” and “six half steps up” mean the same thing.
Two words that trip people up. A half step is a distance between two notes, not a kind of note — every key on the piano, black or white, is a full note in its own right, so an octave holds twelve notes, not “twelve halves.” A whole step is simply two half steps: skip one key. The names come from the major scale, where most steps are two keys wide and a couple are one key wide, so the bigger one was called whole and the smaller one half. (Unrelated: whole note and half note also exist, but they describe how long a note lasts, not how far apart two notes are.)
| Degree | Half steps (keys) above the root | In A | What it is |
|---|---|---|---|
| 1 | 0 | A | the root — home |
| ♭3 | 3 | C | lowered third |
| 4 | 5 | D | fourth |
| ♭5 | 6 | E♭ | lowered fifth — the blue note |
| 5 | 7 | E | fifth |
| ♭7 | 10 | G | lowered seventh |
Why the odd names — why ♭3 and not just 3? The plain numbers 1 to 7 belong to the major scale, the do-re-mi scale that everything else is measured against; in A it runs A B C♯ D E F♯ G♯. A sign (♭) in front of a number means “that note, one key lower.” So ♭3 in A is C, one key below the major scale’s C♯. The blues lowers its third, fifth, and seventh — that lowering is what “flattening” means, and it is most of the flavour.
One spelling note: the keyboard labels black keys with sharps (D♯), while blues writing spells the same key as a flat (E♭). It is one key with two names — nothing is out of tune. Click a chip below to hear each degree in A.
3. Start with five notes: the minor pentatonic
Before the blues scale, meet the scale it is built from. Take degrees 1 ♭3 4 5 ♭7 — five notes — and you have the (“penta” is Greek for five). Nothing in it sits right next to anything else: every note is at least two keys from its neighbours, so no two notes rub against each other. That is why it is the first solo scale most guitarists learn — you can play its notes in almost any order over a blues or rock song and nothing sounds wrong. Press play and listen to how open and even it sounds.
4. Add one note: the blue note
Now squeeze one more key in: the ♭5 — six keys above the root, sitting between the 4 and the 5 with no gap on either side. In A that key is E♭. That single note is the entire difference between the minor pentatonic and the blues scale. Five notes become six: 1 ♭3 4 ♭5 5 ♭7.
Flip the toggle below and watch which key changes — a red dot (locked out) becomes a green ♭5 (in the scale). Play both versions back to back and listen for the extra step in the middle of the run. That crunch is the blues.
Minor pentatonic is blues scale with a note removed — flip the toggle to see which key comes back.
5. Why it sounds “blue”
The ♭5 is restless for two reasons. First, its distance from the root — six keys, exactly half of the twelve-key octave — is the interval musicians call a , the most unsettled sound in Western music. Second, it is wedged between two notes that are already in the scale, so it never gets to sit still: it wants to slide up into the 5 or fall back to the 4. Press Hear the slide to hear 4 → ♭5 → 5.
Blues singers and guitarists do not treat this as a fixed key at all. They bend into it, landing in the crack between E♭ and E. Those in-between pitches are , and they are older than the blues — they come out of work songs, field hollers, and spirituals. A piano cannot bend, so the blues scale freezes the bend onto the nearest key. What you are playing here is the piano’s honest approximation of a note that, on a voice or a guitar, lives between the keys.
6. What to do with it
You now know the whole scale. Pick the root that matches your song — guitar blues usually lives in A or E; the picker at the top moves everything. Keep the lock on and play the green keys in any order: with the lock on there are no wrong notes. Land on 1 or 5 when you want a phrase to feel finished, and treat ♭5 as a note you pass through, not one you stop on. Then take it to a — What is the blues? covers the form and the shuffle the scale sits on.
Quick reference
- Formula
- 1 – ♭3 – 4 – ♭5 – 5 – ♭7
- In A
- A – C – D – E♭ – E – G