A pentatonic scale is a scale with five notes to the octave, instead of the usual seven. It is built by taking a scale you already know and dropping the two notes that create the most tension, which leaves five that sit together easily. That is why it turns up almost everywhere, from blues and rock solos to folk tunes and pop hooks, and in music across much of the world.
Plain theory, no instrument required. It works the same on a piano, a guitar, or in a piano roll, in any key and any style.
A pentatonic scale is a scale made of five notes, rather than the seven of a full major or minor scale. The name comes from the Greek for five, and that is all it means: five notes chosen to lean together and leave out the pitches that would otherwise clash, which is what gives the scale its open, forgiving sound.
The two you meet most are the major pentatonic and the minor pentatonic. Both are five note selections taken from a scale you already know, and, as it turns out, one is just the other started from a different note. Everything here sits on top of the ordinary seven note scales, so if those are not yet solid our guide to scales and keys sets them up first.
The trick in both cases is the same. A seven note scale has two places where two of its notes sit only a semitone apart, and those close pairs are where most of the friction in a scale comes from. Take out the notes that cause those clashes and you are left with five notes spaced widely enough that almost any two of them sound comfortable together.
The major pentatonic scale is a major scale with its fourth and seventh notes removed, leaving five notes: scale degrees 1, 2, 3, 5 and 6. Worked from C, the C major scale is C, D, E, F, G, A, B; drop the fourth, F, and the seventh, B, and you are left with C, D, E, G and A. That is the C major pentatonic.
The fourth and the seventh are removed for a reason. In a major scale the seventh sits just a semitone below the home note and pulls hard toward it, and the fourth sits a semitone above the third and rubs against it. Those are the two sharpest points of tension in the scale, so taking them out leaves five notes with no semitone clashes at all. Whatever order you play them in, they tend to agree.
| C major scale | Degree | In the pentatonic? |
|---|---|---|
| C | 1 | Yes |
| D | 2 | Yes |
| E | 3 | Yes |
| F | 4 | Removed |
| G | 5 | Yes |
| A | 6 | Yes |
| B | 7 | Removed |
Start the same idea on a different note and you get a different major pentatonic, using whatever sharps or flats keep the spacing identical. The note names change; the five note shape does not.
The minor pentatonic scale is a five note scale with the degrees 1, b3, 4, 5 and b7, that is the root, the flat third, the fourth, the fifth and the flat seventh. Worked from A that gives A, C, D, E and G. You can also read it as the natural minor scale with its second and its flat sixth taken out, which removes that scale's two semitone clashes in the same way the major pentatonic does.
Here is the useful part. The A minor pentatonic uses exactly the same five notes as the C major pentatonic; the two simply start in different places and treat a different note as home. Scales that share a set of notes like this are called relative, and it works just as it does for full scales, where A minor is the relative minor of C major. Our guide to scales and keys explains that relative relationship in full.
| Scale | Degrees | Notes |
|---|---|---|
| Major pentatonic (in C) | 1 2 3 5 6 | C D E G A |
| Minor pentatonic (in A) | 1 b3 4 5 b7 | A C D E G |
Because they are the same notes, a solo written over a piece in C major and one written over its relative A minor can draw on the very same five pitches, which is one reason players think of the major and minor pentatonic as two sides of a single shape.
The pentatonic scale is popular because leaving out the two notes that clash most means almost nothing you play sounds wrong. With only five agreeable notes to pick from, a melody or a solo tends to land well even when you are improvising and not thinking hard about theory, which is a large part of why the scale is a backbone of blues, rock, folk and pop, and why versions of it appear in traditional music all over the world.
A close relative shows how far the shape stretches. The blues scale is usually described as the minor pentatonic with one extra note added, a flat fifth known as the blue note. In A that slips an Eb between the D and the E, giving A, C, D, Eb, E and G, and it is that one added note, used in passing, that gives blues and rock much of their characteristic ache.
None of this makes the pentatonic a rule you have to obey. Notes from outside it are not forbidden and are often what makes a line interesting, but the five notes give you a base that is very hard to fall off. And because a pentatonic is defined by the pattern of gaps between its notes rather than by particular letters, the same shape carries its character to any starting note, the point our guide to musical intervals makes about distances holding steady wherever you move them.
We built ARGISH to make a scale quick to hear. It is a self-playing synth locked to a key: pick a key and a mood, and every note it generates stays inside that scale, so you can listen to how the notes sit and sound together instead of working them out on a page. It is a fast way to hear the difference a handful of notes makes, and to get an ear for how a scale behaves before you write over it.
It runs free in your browser to try, and installs as AU, VST3, AAX or a standalone app when you want it inside your own sessions.
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