What are Intervals in Music?

Musical intervals are part of the language of music. Understanding intervals helps musicians read, speak, hear, and understand the language of music better.

What is an Interval in Music?

Why are Music Intervals Important?

All musicians should learn to recognize music intervals by sight and by sound. Here's why:

Recognizing music intervals by sight helps you read music more fluently. When you can recognize intervals on the staff, reading music becomes faster and easier. With practice, this skill can help you learn to "hear" sheet music in your head without playing it aloud -- just like reading a book silently to yourself. 

Recognizing music intervals by sound helps you understand the music you listen to. If you can recognize intervals by listening, the language of music becomes more familiar to you (just like learning a new spoken language). It also helps you learn to play or sing music by ear, because you can tell precisely how far apart all the pitches should be. 

What Do We Call Music Intervals?

To name an Interval, we give it both a Number and a Quality (examples: Perfect 4th, Major 6th, Minor 2nd, etc.). The number represents the distance between the notes, and the quality represents its sound, feeling, and harmonic use. 

The number of an interval must be determined first, and then the quality. Together, these two elements give a music interval its name. 

Interval Numbers: How to Count Intervals in Music

Like any other distance, intervals are measured in numbers. But instead of counting kilometers or inches, we count diatonic musical notes: the seven natural pitches of the musical alphabet, A - B - C - D - E - F - G. The interval number is the number of letter names (or music staff positions) that it encompasses.

For example: Here is C and E on the Bass staff.  

Here are the three ways to determine the number of an interval:

The larger the number, the farther apart the pitches are. For example, a 7th is bigger than a 2nd, which means the pitches in a 7th interval look and sound farther apart than the pitches in a 2nd interval.

How to Get Better at Identifying Interval Counts

1. Practice counting intervals with letter names. Choose various letter combinations from the music alphabet and practice counting how many letters apart they are. Remember the alphabet is A-B-C-D-E-F-G, repeated over and over. Examples (assume the first letter is the lower note): A to B is a 2nd. F to C is a 5th. With time you will discover you do not need to really count the letters anymore because you will learn to automatically associate various letter combinations with their interval count.

2. Practice counting intervals on the music staff. Pull out some sheet music, choose any pair of notes that are either on top of each other (Harmonic Intervals) or next to each other (Melodic Intervals), and figure out their interval by counting the staff lines and spaces from the first note to the next. Do this over and over. With time you will notice visual clues and learn to recognize each interval by sight instantly, and you will no longer have to count staff positions. This will help you become a much better music reader. 

3. If you're a pianist, practice counting intervals on the white keys. This is also beneficial for singers or other instrumentalists who refer to the piano from time to time, because the piano keys show a consistent visual reference for the distance between notes. Pianists should also practice playing the different intervals on the piano to learn how each interval feels in your hand. Being able to "feel" each interval in the hands by muscle memory (not having to count keys) makes a HUGE difference in a pianist's playing fluency.

What are Interval Qualities in Music?

Once you know the number of a music interval, you can determine its quality. Interval qualities tell more about the sound of an interval, how consonant or dissonant it is, and how it could be used harmonically. 

What Do "Dissonance" and "Consonance" Mean?

Dissonance and consonance are terms that have been used for centuries to describe the quality of music intervals. Their definitions have shifted over time and are subject to interpretation (especially across cultures and genres). Generally speaking, consonant intervals have a sense of stability, resolution, pleasantness, and agreeability, while dissonant intervals have a sense of instability, lack of resolution, tension, and disagreeability. The two words are also mutually exclusive: if an interval more consonant it is less dissonant (and vice versa).

All interval qualities have some level of dissonance or consonance. Both consonant and dissonant intervals are used to create music, and how they are used affects the mood and how the line of music resolves. An Augmented 2nd and a Minor 3rd may sound the same if no context is given, but a composer will selectively choose to write the interval as one or the other based on musical context as well as their intended mood and desire for the performer's interpretation. 

How to Determine Interval Qualities

Every music interval is one of these 5 Interval Qualities: Perfect, Major, Minor, Augmented, or Diminished (more info on each of these below). 

The quality of an interval is determined by the number of semitones (also called "half steps") that it encompasses, in conjunction with the interval number. BOTH the interval count and number of semitones must be considered together for two reasons:

Here are some examples of why we have to consider both interval count and semitones when determining an interval's quality.

Reason 1: Two intervals with the same Interval count and a different number of semitones look similar on the music staff, but they have different qualities, harmonic uses, and names. 

Reason 2: Two intervals with a different Interval count and the same number of semitones sound similar, but they look different on the music staff and have different qualities, harmonic uses, and names. 

How Do You Identify Interval Qualities?

You can determine an interval's quality by referring to the Major scale (the most commonly used scale in Western music and much of the world). Every note in the Major scale is either a Major interval or Perfect interval above the first note of the scale.

If the interval matches that of the 1st, 4th, 5th, or 8th (octave) note in a Major scale, its quality is Perfect. If it matches the 2nd, 3rd, 6th, or 7th note in a Major scale, its quality is Major. 

If the interval isn't Perfect OR Major, the Major scale can still help you determine its quality. Identify which Major scale interval most closely resembles the interval you want to qualify, and then count the semitones. If the Interval resembles a Perfect or Major interval but is one semitone larger, it's Augmented. If it resembles a Major interval but is one semitone smaller, it's Minor. If it resembles a Perfect interval but is one semitone smaller, it's Diminished. And if it looks like it might be Minor but is one semitone even smaller, it is Diminished.

To learn more about each of the 5 Interval Qualities, click each Tab below.

How to Identify Interval Qualities on the Piano

If you know already know the interval number but not its quality, you can figure this out on the piano because all the keys (white and black) are exactly one semitone apart. A semitone is the distance between one piano key and the very next adjacent key (whether it is black or white). 

From the starting key, count every semitone (each white or black key you pass) until you reach the other key in your interval. 

What About Intervals Larger than One Octave?

Intervals that are smaller than or equal to one octave are called simple intervals. Intervals that are larger than an octave are called compound intervals. Compound intervals can be considered a stack of simple intervals. They can be broken down into one or more octaves plus one simple interval. 

For example: Here is a 10th. This is composed of an octave and a 3rd, so it can be called either a 10th or a compound 3rd. 

Counting staff lines reveals that this interval is a 10th. Counting letter names (C-D-E) suggests this interval is a 3rd, but because there is more than an octave difference it is clarified as a compound 3rd. 

So the interval count for a compound interval can be determined two ways. One is by counting staff lines, which give you the actual number (the previous example is a 10th). The other is by counting letter names and factoring in the octave difference, which will give you its compound number (the previous example is also a compound 3rd). 

The quality of a compound interval is the same as the quality of the simple interval on which it is based. In the example above, the 10th can be broken down into an octave and a Major 3rd, which makes it a compound Major 3rd or a Major 10th (either name is correct). A Major 10th will sound like a Major 3rd, but more "open"; the octave difference gives it a broader feel.