A scale is a ladder of notes from a root to its octave. Learn how the major and minor scales are built, why we bend the minor, and how pentatonics, the blues note and the modes all grow from the same few steps.
Between one note and the next there are only two step sizes: a whole step (2 semitones) and a half step (1 semitone). A scale is just a fixed recipe of those steps.
The major scale is W–W–H–W–W–W–H. Follow that from any note and you always land on a major scale. Change the recipe and everything else on this page appears.
Everything starts here. Its bright, finished sound comes from two things: a major 3rd near the bottom, and a 7th just a half step below the octave — a "leading tone" that leans hard toward home. On the keyboard, watch where the steps are whole (a key skipped between) or half (right next door).
Start a major scale on its 6th note instead of its 1st and you get the natural minor — the very same seven notes, but a new home (this is why C major and A minor are "relatives"). Measured from its own root, three notes now sit a semitone lower than the major scale's: the ♭3, ♭6 and ♭7. That lowered 3rd is the sound of "sad." Its recipe is W–H–W–W–H–W–W.
The scale is ancient. Greek theorists worked out the seven-note scale by dividing a vibrating string into whole-number lengths on a one-string instrument called the monochord. Halve the string for the octave, take two-thirds for a fifth — the whole ladder falls out of one string and some simple maths.
A thousand years later the monk Guido of Arezzo used that same one-string tool to teach choirs to read music, and gave the notes their singing names — ut–re–mi–fa–sol–la, the ancestors of today's do–re–mi. On a fretted string those steps become something you can see and count: each fret is one half step, so a scale is just a pattern of fret jumps.
Imagine a string tuned to your root. Play it open (step 1), then climb: a whole step is 2 frets, a half step is 1 fret. Seven jumps and you're home, an octave up at fret 12.
The natural minor has one weakness. Its top note, the ♭7, sits a whole step below the tonic — too far to pull strongly home. Music wants gravity: a note a half step below the tonic that aches to resolve up to it — a leading tone.
So we raise the 7th. That gives the harmonic minor (♭3, ♭6, ♮7) — now the ending pulls home hard. But raising it opens a wide gap below: an augmented 2nd, three frets between the ♭6 and the ♮7 — that unmistakable, exotic colour (you can see the "1½" jump on the string).
To smooth the climb, we can raise the 6th too: the melodic minor (♭3, ♮6, ♮7), which sounds almost major on the way up and usually relaxes back to natural minor coming down. Both scales exist for one reason — to give the tonic gravity. Singers had done exactly this for centuries, raising the 7th at cadences (musica ficta), the practice Fux later codified in Gradus ad Parnassum.
A scale's tension lives in its half steps. In the major scale they fall between the 3rd–4th and the 7th–8th — and the 4th and 7th are the restless notes that make them. Take those two out and five notes remain that never clash: the major pentatonic (1 2 3 5 6).
Do the same to the minor scale — drop the 2nd and the ♭6 — and you get the minor pentatonic (1 ♭3 4 5 ♭7). Fewer notes, no wrong turns: it's why pentatonics are usually the first scales anyone learns, and the sound of folk music the world over. (The faded notes below are the ones we removed.)
Take the minor pentatonic and sneak in one extra note — a flattened 5th (♭5), tucked between the 4th and the 5th. That's the blue note (shown in blue below): it belongs to neither major nor minor, it lives in the cracks, and sliding into and out of it is the whole sound of the blues.
The fuller story — the 12-bar form, dominant 7ths and bent notes — is on the Blues Theory page →
Play only the white keys of a piano but begin on a different note each time, and you get seven scales built from the same notes that each feel completely different — the modes. Each is given away by a single signature note.
These are the old church modes, the scales Fux teaches in Gradus ad Parnassum. In that world a melody in Dorian, Mixolydian or Aeolian would raise its 7th at the cadence (musica ficta) to borrow the major scale's pull home — the one exception being Phrygian, whose ♭2 gives it a falling cadence all its own. Below, hear them all from the same root so each signature note stands out against a fixed home.
| Mode | Signature note | Character |
|---|
Tap a name to open it in the scale library below.
| Scale | Step pattern | Notes |
|---|
Any scale, any root — mapped across the whole piano or the full neck of each string instrument. The complete picture to study or print.
Tip: W = whole step (2 semitones / 2 frets), H = half step (1). A "1½" is three semitones — a whole step plus a half.