An interval is the distance from one pitch to another. These steps and leaps between notes are the building blocks of chords and melodies—in other words, intervals are kind of a big deal! Two notes played at the same time make a “harmonic” interval and two notes played consecutively make a “melodic” interval.
To confidently identify intervals, you’ll first need to master your understanding whole-steps and half-steps—also known as tones and semi-tones. A half-step (semi-tone) is two different notes with the smallest possible distance between them—for example, B up to C, or E down to Eb. Think of two frets right next to each other on a guitar, or two keys (including the black keys) right next to each other on the piano. A whole-step (tone) is made up of two half-steps—for example, B up to C#, or E down to D.
ABCs and 123s
Every interval is first identified by a number that we find by counting all the note names (A, B, C, D, etc.) from the first note to the second, including the notes themselves. (At this point, don’t worry about any sharps or flats.) For B up to F#, for instance, name the notes B, C, D, E, F to get the number 5, or an interval of a fifth.
Number 1 is a unison (the two notes are exactly the same) and 8 is an octave; in between, 2 gives you an interval of a second, 3 is an interval of a third, and so on. Notice that intervals with odd numbers always go “line to line” or “space to space” on the staff. Intervals with even numbers always go “line to space” or “space to line.”
Step by Step
Next, we determine the interval quality. Here, we’ll focus on the most common qualities—perfect, major, and minor.
- Unisons, fourths, fifths, and octaves are perfect.
- Seconds, thirds, sixths, and sevenths can be either major or minor.
The most fool-proof method for correctly identifying whether an interval is major or minor is to count the number of half-steps it contains. As you become more comfortable, you may begin to think in “shortcuts” that combine half-steps, whole-steps, and other common intervals—making for much less counting!
| Interval | Abbreviation | Number of Half-Steps | Shortcut |
| Unison | P1 | 0 | N/A |
| Minor second | m2 | 1 | N/A |
| Major second | M2 | 2 | WHOLE-STEP |
| Minor third | m3 | 3 | WHOLE-STEP + HALF-STEP |
| Major third | M3 | 4 | 2 WHOLE-STEPS |
| Perfect fourth | P4 | 5 | M3 + HALF-STEP |
| Tritone* | TT | 6 | 3 WHOLE-STEPS |
| Perfect fifth | P5 | 7 | P4 + WHOLE-STEP |
| Minor sixth | m6 | 8 | P5 + HALF-STEP |
| Major sixth | M6 | 9 | P5 + WHOLE-STEP |
| Minor seventh | m7 | 10 | P8 – WHOLE-STEP |
| Major seventh | M7 | 11 | P8 – HALF-STEP |
| Perfect octave | P8 | 12 | N/A |
*The interval created by 6 half-steps (that is, 3 whole-steps) has a special name—the tritone, abbreviated TT. The tritone is the exact midpoint between a pitch and its octave.
Test Yourself!
Identify each of the intervals below. (Answers are at the bottom of this page.)
ANSWER KEY: 1. Minor sixth (m6) 2. Major third (M3) 3. Perfect fifth (P5)
