Music intervals: name them, count them, hear them
An interval is the distance between two notes. Its name has two parts: a number, like second, third or fourth, which you find by counting letter names, and a quality, like major, minor or perfect, which you find by counting half steps. In this guide, you'll find the full chart, a simple method to name any interval, and reference songs that will help you recognize each one by ear.
The number: count both ends
Let's start with the number. To name the interval from C to E, count the letters, including both ends: C is one, D is two, E is three. So it's a third. From C to G, you count C, D, E, F, G, and you get a fifth. The number ignores accidentals: C to E and C to E♭ are both thirds.
The quality: count the half steps
| Interval | Half steps | From C | Reference song (ascending) |
|---|---|---|---|
| Minor second | 1 | C-D♭ | the “Jaws” theme |
| Major second | 2 | C-D | “Happy Birthday” (hap-py birth-) |
| Minor third | 3 | C-E♭ | “Greensleeves” |
| Major third | 4 | C-E | “When the Saints Go Marching In” |
| Perfect fourth | 5 | C-F | “Here Comes the Bride”, “Hedwig's Theme” |
| Tritone | 6 | C-F♯ or C-G♭ | “The Simpsons” theme |
| Perfect fifth | 7 | C-G | the “Star Wars” main theme |
| Minor sixth | 8 | C-A♭ | “The Entertainer” (the leap at the start of the tune) |
| Major sixth | 9 | C-A | “My Bonnie Lies Over the Ocean”, the NBC chimes |
| Minor seventh | 10 | C-B♭ | “Somewhere” from West Side Story |
| Major seventh | 11 | C-B | sing an octave, then come down a half step |
| Octave | 12 | C-C | “Over the Rainbow” (some-where) |
Now for the quality. Seconds, thirds, sixths and sevenths are major or minor. Fourths, fifths, unisons and octaves are perfect. Any of them can also be augmented, which means a half step wider, or diminished, a half step narrower. The augmented fourth, exactly three whole steps, is called the tritone.
- Steps
- 5 letter names, from C4 to G4
- Make-up
- 3 whole steps and 1 diatonic half step
- Half steps
- 7 half steps on a keyboard
- Inversion
- perfect fourth
- Type
- perfect consonance
Inversion
To invert an interval, you move the lower note above the upper one. C up to E, a major third, becomes E up to C, a minor sixth. Two rules help here. First, the numbers add up to 9: a third and a sixth, a fourth and a fifth, a second and a seventh. Second, the quality flips: major becomes minor, augmented becomes diminished, and perfect stays perfect.
Consonant and dissonant
Traditional theory sorts intervals into three groups. The perfect consonances are the unison, the fifth and the octave. The imperfect consonances are the thirds and sixths. The dissonances are the seconds, the sevenths, and the augmented and diminished intervals. The fourth depends on context. And remember, a dissonance isn't a mistake: it's tension that wants to resolve, and much of music's expression depends on it.
Tip: link each interval to the opening of a tune you know well, then check it in the interval lab.