Scale theory

What is a scale? The easiest way to explain scales is like a collection of notes that of a musical reason have been grouped together. The benefit of knowing scales in music is that you know how to orient yourself among notes. This will among other things give you a foundation for improvising – notes in a particular scale always sound good played together – and composing.

You don't have to read notes to be able to learn scales (but it is always good to be acquainted with reading notes). Neither do you have to know a lot of chords, but if you already know some chords the scales will be much easier to relate to and subsequently memorize. And by knowing scales you will be able to learn chord easier - chords derive from scales.


In many cases a scale consists of seven notes – this is the case of the major and minor scales. The scales are also octave-repeating which means the pattern of notes is the same regardless if you play a scale on the left, the middle or the right side of the keyboard.

On a full scale piano, there is a total of 88 keys, but there are only twelve different notes which are repeated from low to high tones, from the base to the treble.

keyboard illustrated with notes
In the illustration above, you can see twelve tones that make one octave and these notes also form a Chromatic Scale). One important thing is that C# is sometimes written Db and D# is sometimes written Eb and so on. These are called enharmonic notes and how they are written depends on the key they belong to. The symbols after the letter (accidentals) are known as sharps and flats. C# is spelled "C sharp" and Db is spelled "D flat". This is of course only theory, but is nevertheless good to know about.

Let's take the G major scale as an example:
G scale
The notes are G - A - B - C - D - E - F# - G.

Let's now look at the F major scale:
F scale
The notes are F - G - A - Bb - C - D - E - F.

We have seen two different scales where we use sharps (#) and flats (b). The rule that decides if the note is raised or lowered depends on the intervals between notes in the scale. In the examples above F# is a raised F and Bb is a lowered B.

On some occasions you may observe two sharps or flats in adjunction to a described note in a piano score. These are called double-sharps and double-flats. The reason these are used needs a theoretical explanation. Let us take the key of D# as an example, this key includes both D# and D, but to make it functional in a score with a key signature it should be D# and C## otherwise you would be lured to play a D# instead of a D.

The same thing sometimes occurs when the notes of scales or chords are written out. For example, the C# Major Scale could correctly be written: C#, D#, F, F#, G#, A#, B#, C#. Notice that B# is written instead of C. B# is not existing in reality and the note should be played as a C. (On C is sometimes written instead of B## anyway to avoid confusing. There is many beginners using the sites and things like B## would clearly confuse some of these and in the overviews the formally correct notes are presented below.)

Changing keys and scales

Music pieces are written in a certain key, like Brandenburg Concerto No 1 in F Major by J.S. Bach. It would be feasible to re-arrange this concerto to another key, like for example D Major. It would still be the same to a large extent, but the timbre would be different.


Most songs start and end with the same tone which is the first note, or tonic, in the scale. Then you play notes from a scale you could hear that the music seems to gravitate towards the first note, it is like some tension is left until you have reached that first note. This phenomenon is called tonality.

Scale degrees

There is also something called scale degrees that refers to the relations of every particular note in the scale in a general basis. These have roman numbers as you can see below:

Tonic (I) — the first note of a scale that the scale is based upon, sometimes called the root.
Super tonic (II) — second scale degree, one step above the tonic.
Mediant (III) — third scale degree with a position halfway between the tonic and the dominant.
Subdominant (IV) — fourth scale degree, a fifth below the tonic and next to the dominant.
Dominant (V) — fifth scale degree
Submediant (VI) — sixth scale degree and sometimes called supermediant.
Subtonic (VII) — seventh scale degree which is also referred to as leading tone because it musically "leads" back to the tonic.

Why should you learn these terms? One great thing about knowing them is that you can have a better understanding of scales and chords in an abstract way. For one of many reasons, this will help you in transposing music to another key and give you hints while you are composing music.

To show a concrete example: in blues you very often use the tonic (I), subdominant (IV) and the dominant (V). This can, for example, be a chord progression and by knowing this theoretical relationship you can play blues in all keys by using the same intervals.


Intervals in music describe the distance between two notes. The most common intervals that you should be familiar with are: prime, second, third, fourth, fifth, sixth, seventh and octave. See these intervals illustrated below:


Intervals can also be used to describe the structure of a scale category. For example, the Major Scale can be written like: 1, 2, 3, 4, 5, 6, 7 and the Natural Minor can be written like: 1, 2, b3, 4, 5, b6, b7, referring to the intervals.


Another way to describe the structure of a scale is with the word steps which refer to the distance between notes. The most often used terms are half steps and whole steps. Between C and C# there is one half step and between C and D there is one whole step.

In the scale overviews on this site you will see "semi-notes" (equivalent to half steps) and "formulas" used also to describe the scales. It is mainly the same thing only described in different ways. For the Major Scale this will look like: 2 - 2 - 1 - 2 - 2 - 2 - 1 (semi-notes) and Whole, Whole, Half, Whole, Whole, Whole, Half (formula).

Continue and learn more about basic piano terms ...