Major scale

The major scale (or Ionian mode) 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 (from Latin "octavus", the eighth).

The simplest major scale to write is C major, the only major scale not requiring sharps or flats:

The major scale has a central importance in Western music, particularly that of the common practice period and in popular music.

In Carnatic music, it is known as Sankarabharanam. In Hindustani classical music, it is known as Bilaval.

The intervals from the tonic (keynote) in an upward direction to the second, to the third, to the sixth, and to the seventh scale degrees of a major scale are called major.

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 (a red u-shaped curve in the figure), and "half" stands for a semitone (a red angled line in the figure).

Whole steps and half steps are explained mathematically in a related article, Twelfth root of two. Notably, in terms of the sound frequency ratio in equal temperament, a whole tone has twice the sound frequency ratio of a semitone and an octave has twelve half steps (semitones) spaced equally. The sound frequency doubles for corresponding notes from one octave to the next. The ratio is 3/2 = 1.5 for a perfect fifth, for example from C to G on a major scale, and 5/4 = 1.25 for a major third, for example from C to E.