Music Theory Crash Course: Intervals

What is an interval? Of course, in music theory, there is always, always a long-winded answer to everything. We could drown you with talk of frequencies and ratios and blah and blah, but we're not going to do that. Quite simply, an interval measures the space between two pitches.

Why is it important to understand intervals? Because intervals are the building blocks of chords and scales. Chords and scales are the backbone of melody and, well, Western music as we know it.

The Smallest Intervals

The smallest interval that can be notated is a unison, which is the space between one pitch and, yes, the same pitch. Choral singers encounter unisons when, for example, the soprano section and the alto section sing the same pitch. Though it may seem counterintuitive, unison technically qualifies as an interval.

Besides unison, the smallest interval is the half-step (H). Imagine a piano keyboard. A half-step is the distance between one white key and any adjacent key: C to C-sharp, for example, or B to C. Another name for a half-step is a "minor second."

A whole-step (W) is—you guessed it—equal to two half-steps. So, one half-step + one half-step = one whole-step. A whole step is the distance from C to D, for example, or from E to F#. Another name for a whole-step is a "major second.

Labeling Intervals

Any interval larger than a whole-step is made up of a combination of half-steps and whole-steps. But how do we quickly identify the various combinations of half-steps and whole-steps? By giving them labels. That's where the terms major, minor, augmented, diminished, and perfect come in.

These terms are often abbreviated as such: major = M, minor = m, augmented = A or +, diminished = d or º, perfect = P.

M6, then, is the shorthand way to write "major 6th" and is in no way associated with firearms—at least not within a musical context.

We've already mentioned that one half-step is called a minor 2nd (m2) and that one whole-step is called a "major 2nd" (M2). Below is a listing of other intervals.

Why This Is Important

We know we are taking you down to the atomic level with our exposition on intervals. But we promise—this is important! You need to understand intervals in order to understand chords and scales. It's important to understand chords and scales in order to understand melody.

More Music Theory Crash Courses

1) Introduction

Why should we learn about music theory?

2) The Very Basics

A snapshot look at the staff and note placements.

3) Scales

A scale is a series of ascending and descending notes. The way a scale sounds depends on the interval relationship between the pitches.

4) Chords

Chords are made up of linked intervals.

5) Key Signatures

A key signature is a bank of either sharps (#) or flats (b) found at the beginning of each staff to the right of the clef symbol.