The major scale is one of the most commonly used musical scales, especially in Western music. It is one of the diatonic scales. Like many musical scales, it is made up of seven notes: the eighth duplicates the first at double its frequency so that it is called a higher octave of the same note. The simplest major scale to write is C major, the only major scale not requiring sharps or flats:
A major scale is a diatonic scale. The sequence of intervals between the notes of a major scale is: where "whole" stands for a whole tone, and "half" stands for a semitone. A major scale may be seen as two identical tetrachords separated by a whole tone. Each tetrachord consists of two whole tones followed by a semitone. The major scale is maximally even.
If a piece of music is in a major key, then the notes in the corresponding major scale are considered diatonic notes, while the notes outside the major scale are considered chromatic notes. Moreover, the key signature of the piece of music will generally reflect the accidentals in the corresponding major scale. For instance, if a piece of music is in E major, then the seven pitches in the E major scale are considered diatonic pitches, and the other five pitches are considered chromatic pitches. In this case, the key signature will have three flats. The figure below shows all 12 relative major and minor keys, with major keys on the outside and minor keys on the inside arranged around the circle of fifths. The numbers inside the circle show the number of sharps or flats in the key signature, with the sharp keys going clockwise, and the flat keys counterclockwise from C major The circular arrangement depends on enharmonic relationships in the circle, usually reckoned at six sharps or flats for the major keys of F = G and D = E for minor keys. Seven sharps or flats make major keys that may be more conveniently spelled with five flats or sharps.
There are two scales that go by the name melodic major scale: The first is the fifth mode of the jazz minor scale, which can be thought of as the major scale with a lowered sixth and seventh degree or the natural minor scale with a raised third.
The second is the combined scale that goes as Ionian ascending and as the previous melodic major descending. It differs from melodic minor scale only by raising the third degree to a major third.