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Understanding Music Intervals

Intervals are the DNA of music. Master them, and you'll understand why chords sound the way they do and why certain notes "work" together.

What Is an Interval?

An interval is simply the distance between two notes. That's it. When you play two notes—either simultaneously (harmonic interval) or one after another (melodic interval)—the space between them has a name.

Understanding intervals answers questions like:

The Building Blocks: Half Steps and Whole Steps

On guitar, intervals are easy to visualize:

Every interval can be measured in half steps. This makes the guitar wonderfully logical once you understand the pattern.

The Complete Interval Reference

Half Steps Interval Name Sound/Feel Song Example
0 Unison (same note) Same pitch —
1 Minor 2nd Tense, dissonant Jaws theme
2 Major 2nd Stepping up Happy Birthday (first 2 notes)
3 Minor 3rd Sad, dark Greensleeves
4 Major 3rd Happy, bright When the Saints Go Marching In
5 Perfect 4th Strong, military Here Comes the Bride
6 Tritone (Aug 4th/Dim 5th) Unstable, devilish The Simpsons theme
7 Perfect 5th Powerful, open Star Wars theme
8 Minor 6th Mysterious The Entertainer
9 Major 6th Warm, nostalgic NBC chime
10 Minor 7th Bluesy, jazzy Star Trek theme
11 Major 7th Dreamy, unresolved Take On Me (chorus)
12 Octave Same note, higher Somewhere Over the Rainbow

The Three Interval Qualities

Perfect Intervals

The unison, 4th, 5th, and octave are called "perfect" intervals. They have a pure, stable, consonant sound. Power chords use the perfect 5th—that's why they work in any context without sounding major or minor.

Major and Minor Intervals

The 2nd, 3rd, 6th, and 7th come in major and minor versions. Major intervals are one half step larger than their minor counterparts.

💡 The "Major vs Minor" Secret

The entire difference between a major chord and a minor chord is one half step on the 3rd. That's it! Lower the 3rd by one fret, and any major chord becomes minor.

Diminished and Augmented Intervals

When you shrink a perfect or minor interval by a half step, it becomes diminished. When you expand a perfect or major interval by a half step, it becomes augmented.

Intervals on the Guitar Fretboard

Here's the beautiful thing about guitar: intervals have consistent shapes that work anywhere on the neck (with a slight adjustment for the B string).

Same-String Intervals

On any single string: Minor 2nd = 1 fret apart Major 2nd = 2 frets apart Minor 3rd = 3 frets apart Major 3rd = 4 frets apart Perfect 4th = 5 frets apart Tritone = 6 frets apart Perfect 5th = 7 frets apart Octave = 12 frets apart

Cross-String Intervals (E, A, D, G strings)

From any note on strings 6, 5, 4, or 3: Perfect 4th = Next higher string, same fret Major 3rd = Next higher string, 1 fret back Minor 3rd = Next higher string, 2 frets back Major 2nd = Next higher string, 3 frets back

The B String Exception

When crossing from the G string to the B string, add 1 fret to all shapes. This is because B is tuned a major 3rd above G (instead of a perfect 4th like the other strings).

Why Intervals Matter for Guitar Players

Building Chords

Every chord is just a stack of intervals:

Understanding Scales

Scales are defined by their interval patterns:

Improvising

When you know intervals, you can:

🎯 Practice Intervals Visually

FretTrain's Intervals Mode lets you select a key and toggle individual scale degrees on/off. See exactly how intervals map across the entire fretboard.

Try Interval Mode →

Ear Training: Recognizing Intervals

The ultimate goal is to hear intervals, not just see them. Here's how to train your ear:

  1. Associate each interval with a song — Use the song examples in the table above
  2. Sing intervals — Before you play them, try to sing from one note to the other
  3. Practice "interval dictation" — Have someone play two notes and you name the interval
  4. Use ascending AND descending — Intervals sound different going up vs. down

Quick Reference: Interval Shortcuts

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