Consonance and dissonance describe how stable an interval sounds: consonant intervals such as the octave, perfect 5th and major 3rd sound stable and restful, while dissonant intervals such as the minor 2nd and the tritone sound tense and unstable, and music moves between the two.
What is consonance vs dissonance?
Consonance and dissonance are the two poles of harmony: consonant intervals sound stable, restful and finished, while dissonant intervals sound tense, unstable and in need of resolution. The octave, the perfect 5th and the major and minor 3rds are consonant; the minor 2nd, the major 7th and the tritone are dissonant. The distinction is not a matter of taste alone: it comes from the way sound waves interact, with consonant intervals having simple frequency ratios and dissonant intervals having complex ones that create audible beating between the notes. Music lives in the movement between consonance and dissonance. A piece that was entirely consonant would sound dull and static, while a piece that was entirely dissonant would sound chaotic and exhausting. Composers create interest by setting up dissonance and then resolving it to consonance, and the listener's pleasure comes largely from that cycle of tension and release. A dominant 7th chord is dissonant because of its tritone, and its resolution to a consonant major triad is one of the most satisfying moments in music.
How consonance and dissonance work
The traditional ranking, from most consonant to most dissonant, runs: octave and unison, perfect 5th, perfect 4th, major and minor 3rds, major and minor 6ths, and then the dissonances, major and minor 2nds, major and minor 7ths, and the tritone. The 3rds and 6ths are called imperfect consonances, because they sound pleasant but less stable than the perfect intervals, and they are the intervals that give chords their major or minor colour. The 2nds and 7ths are the sharpest dissonances, because the notes sit close together and their sound waves interfere strongly. Context changes everything, though. A perfect 4th is consonant on its own, but against the bass note it is treated as a dissonance in classical harmony, because it wants to resolve down to a 3rd. A minor 2nd is harsh in isolation, but in a jazz chord it can be a colourful extension. And what counts as dissonant has changed over history: the 3rd was once considered dissonant, and the tritone was once banned, while modern ears accept both happily. The C major guitar chord is built from consonances, the root, 3rd and 5th, while the G7 guitar chord adds the dissonant tritone.
Worked example — consonance and dissonance in C major. Play C and G together, a perfect 5th, and listen for the open, stable sound. Now play C and E together, a major 3rd, and notice that it sounds pleasant but less hollow than the 5th. Now play C and F together, a perfect 4th, and notice that it sounds stable on its own but slightly restless. Now play C and F# together, a tritone, and the tension is obvious, and the ear wants the F# to move to G. Finally play C and B together, a major 7th, and the clash is sharp, with the two notes almost touching. That journey, from the 5th to the 7th, is the whole consonance-dissonance spectrum in one exercise.
How to practise hearing consonance and dissonance
Train your ear to rank intervals by stability, not by liking: the question is whether the interval sounds finished or whether it wants to move.
- Play the intervals from C to each white key on the piano, and rank them from most stable to least stable, without looking at their names.
- Play a consonant interval, then a dissonant one, then resolve the dissonant one by moving one note a semitone, and listen for the release.
- Play the I–V–vi–IV progression in C major and notice that the V chord, G, contains the most tension, while the I chord, C, contains the least.
- Sing a perfect 5th above a root note, then a minor 2nd, and feel the difference between the open sound and the pinched sound.
- Use the interval calculator to check the intervals you are hearing, and confirm which ones are consonant and which are dissonant.
Common mistakes
- Thinking dissonance means bad — Dissonance is not a mistake: it is the tension that makes resolution satisfying. Music without dissonance is boring, and the best composers use dissonance deliberately, not accidentally.
- Treating consonance as a fixed list — Whether an interval sounds consonant depends on its context, its register and its voicing. A perfect 4th against the bass is dissonant in classical harmony, even though the same interval sounds consonant on its own.
- Resolving every dissonance immediately — Some dissonances are meant to linger, especially in jazz and modern music, where a 9th or an 11th adds colour without needing to resolve. Learn the rules first, then learn when to break them.
Quick reference
This table ranks the intervals within one octave from the most consonant to the most dissonant, so you can see the whole spectrum in one place. The perfect intervals sit at the top, the 3rds and 6ths sit in the middle as imperfect consonances, and the 2nds, 7ths and the tritone sit at the bottom as dissonances that want to resolve.
| Interval | From C | Consonant or dissonant |
|---|---|---|
| Octave | C – C | Perfect consonance |
| Perfect 5th | C – G | Perfect consonance |
| Perfect 4th | C – F | Perfect consonance |
| Major 3rd | C – E | Imperfect consonance |
| Minor 3rd | C – D# | Imperfect consonance |
| Major 6th | C – A | Imperfect consonance |
| Minor 6th | C – G# | Imperfect consonance |
| Major 2nd | C – D | Dissonance |
| Minor 2nd | C – C# | Dissonance |
| Major 7th | C – B | Dissonance |
| Minor 7th | C – A# | Dissonance |
| Tritone | C – F# | Dissonance |
Play the table on piano from top to bottom, and listen for the sound changing from open and stable to tense and restless as you go down. When you can rank any interval by ear, you will start hearing the tension and release in real music, and your own playing will gain a sense of direction it did not have before.
Frequently asked questions
What is consonance in music?
Consonance is the quality of an interval or chord that sounds stable, restful and finished. The octave, perfect 5th and major and minor 3rds are consonant, and they are the intervals that chords and cadences are built from.
What is dissonance in music?
Dissonance is the quality of an interval or chord that sounds tense, unstable and in need of resolution. The minor 2nd, major 7th and tritone are dissonant, and they create the tension that makes music move forward.
Which intervals are consonant?
The unison, octave, perfect 5th, perfect 4th, major and minor 3rds, and major and minor 6ths. The perfect intervals are called perfect consonances, and the 3rds and 6ths are called imperfect consonances, because they are pleasant but less stable.
Which intervals are dissonant?
The minor and major 2nds, the minor and major 7ths, and the tritone, which is the most dissonant of all. These intervals sound tense because their sound waves interfere, and the ear expects them to resolve to a consonance.
Can a dissonant interval sound good?
Yes. Dissonance creates the tension that makes resolution satisfying, and many beautiful sounds, from the dominant 7th chord to the blues scale, depend on dissonance. The question is not whether an interval is dissonant, but whether its tension is used well.