Intervals are an integral part of music theory. They are the building blocks that allow us to create melodies and harmonies.

Understanding how intervals work is essential for any musician, whether you are a singer, instrumentalist, or composer. In this article, we will explore the basics of intervals and their usage in music theory.

What Are Intervals?

An interval is the distance between two notes. It is measured by counting the number of letter names and accidentals (sharps or flats) between two notes. For example, the interval between C and E is a third because there are three letter names (C, D, and E) in between them.

Types of Intervals

There are two types of intervals: melodic and harmonic. Melodic intervals are played one note after the other, while harmonic intervals are played at the same time.

Intervals can also be classified based on their size. There are four types of intervals based on size:

A perfect interval is when two notes sound perfectly in tune with each other, such as a perfect fifth or octave. Major and minor intervals refer to how many half-steps there are between two notes. Augmented intervals occur when an interval is made one half-step larger than its original size.

Interval Quality

In addition to size, intervals also have a quality based on their scale degree position within a key signature. For example, a C major scale has a natural third (E), but if you play an E flat instead, it becomes a minor third.

Interval Inversion

Intervals can also be inverted, meaning that the lower note becomes the higher note and vice versa. When an interval is inverted, its quality is changed as well. For example, a major third (C-E) becomes a minor sixth (E-C).

How Do Intervals Work in Music Theory?

Intervals are used extensively in music theory to create melodies and harmonies. They are used to create chords, scales, and arpeggios.

For example, a C major chord is made up of the intervals of a root (C), major third (E), and perfect fifth (G). The notes in the C major scale are separated by specific intervals: whole-whole-half-whole-whole-whole-half.

Intervals can also be used to create tension and release in music. Dissonant intervals like minor seconds or tritones can create tension, while consonant intervals like perfect fifths or octaves provide stability.


In conclusion, understanding how intervals work is essential for any musician. Intervals allow us to create melodies and harmonies and provide structure to music theory. By knowing the types of intervals, their quality, and how they work within a key signature, musicians can create beautiful music that resonates with their audience.