Understanding Intervals in Music Theory

While we've previously covered intervals on the piano—explaining them as the distance between two notes measured in semitones—intervals go far beyond a single step or jump. Each interval has a specific name and plays an important role in music theory.

When two notes are identical, we call that a unison. If played on the same instrument and tuned correctly, they sound like a single note. But as soon as the notes begin to differ, intervals begin to shape the sound, emotion, and structure of your music.

If you're just starting out, we recommend pairing this lesson with the Music Theory Cheat Sheet Mousepad PDF or the Music Theory Simplified E-book to help you follow along with diagrams and definitions at a glance.

Intervals are essential for building chords, constructing melodies, and developing your ear for music. They're defined by two characteristics: a number and a quality. The number refers to the distance between two notes, counting both the starting and ending notes. For example, from C to E is called a “third” because it spans C-D-E (three letter names).

Melodic vs Harmonic Intervals

Intervals can be played in two ways: one note after another (melodic intervals) or both notes at the same time (harmonic intervals).

Melodic intervals occur when notes are played in sequence. This is what gives shape to melodies. Think of it as how you sing a tune or play a melody on a single instrument.

Harmonic intervals happen when notes are played together. This forms the basis of chords and harmonies. For example, playing C-E-G together creates a C major chord—a classic harmonic structure.

Interval Numbers and Qualities

Every interval has a number—like second, third, fourth—and a quality—such as perfect, major, minor, augmented, or diminished.

Perfect Intervals

Unisons, fourths, fifths, and octaves are considered perfect intervals. They have a stable, neutral sound and are not labeled as major or minor. For example, C to G is a perfect fifth.

Major and Minor Intervals

Seconds, thirds, sixths, and sevenths can be either major or minor. These intervals affect the mood of a melody or harmony. A major third (C to E) sounds happy, while a minor third (C to E♭) sounds sad or tense.

Major and minor intervals bring color and emotion to your music. Understanding how to identify and use them is one of the fastest ways to improve your songwriting and production skills.

Famous Examples of Intervals in Songs

One of the best ways to memorize intervals is by linking them to songs you already know. Below are well-known tracks that begin with clear examples of specific intervals:

• Perfect Fourth – Star Wars Theme

• Tritone – The Simpsons Intro

• Minor Third – Michael Jackson, “Bad”

• Major Seventh – A-Ha, “Take On Me”

How Intervals Are Used in Music

1. Modulation and Key Changes

Intervals are the building blocks of modulation. To move to a new key, composers use major and minor intervals to shift the tonal center and create contrast within a piece. Learn more about keys in music here.

2. Melodies

Intervals shape the emotional direction of melodies. Larger leaps tend to create drama, while smaller steps (like seconds and thirds) are more lyrical and singable.

3. Harmonization

You can harmonize a melody by adding a second voice using a fixed interval—like a third or sixth above the original note. Try harmonizing a melody using your keyboard or DAW and experiment with interval combinations.

4. Chord Progressions

Chords are formed using stacked intervals. A major triad uses a root, a major third, and a perfect fifth. Understanding how intervals work together helps you write more intentional and emotionally rich chord progressions. Learn how intervals connect to modes.

5. Expression and Color

Intervals aren’t just functional—they also add personality to melodies. A single interval change can shift the mood of a phrase from calm to intense. Experiment with small changes and pay attention to how they affect the listener’s response.

Continue Learning

Intervals are one of the most practical pieces of music theory. They’re used constantly in composing, playing, and producing. If you're looking for a visual and structured way to reinforce what you’ve learned, check out these resources:

• Music Theory Simplified – A beginner-friendly book covering all key music theory concepts with QR video tutorials
• Music Theory Cheat Sheet Mousepad – Keep intervals, scales, modes, and chord formulas right at your fingertips
• Related: Learn the Names of Piano Notes – Get comfortable with note names before exploring intervals deeper
• Related: Half Steps and Whole Steps Explained – The essential foundation for understanding interval distances