Intervals

Intervals don’t take up much time because they are pretty much self-explanatory. They are the distance between two notes. The piano is usually the best guide in explaining this as we go along.

There is a name for the distance between any two notes within one octave. Of course there exist names beyond an octave, but we will be discussing the names within an octave. We will be using the key of C for the examples.

PU – perfect unison

(Although it is redundant, we should mention it. It is simply the distance between the note and itself. Meaning, it is the note. Example: C-C)

m2 – minor second. Example: C-C#(1 half step)
M2 – major second. Example: C-D (2 half steps)
m3 – minor third. Example: C-Eb (3 half steps)
M3 – major third. Example: C-E (4 half steps)
P4 – perfect fourth. Example: C-F (5 half steps)
TT – tritone. Example: C-F# (6 half steps)
P5 – perfect fifth. Example: C-G (7 half steps)
m6 – minor sixth. Example: C-Ab (8 half steps)
M6 – major sixth. Example: C-A (9 half steps)
m7 – minor seventh. Example: C-Bb (10 half steps)
M7 – major seventh. Example: C-B (11 half steps)
P8 – perfect octave. Example: C-C (12 half steps)

These names will be referenced frequently throughout the many guides on this site, in reference to chords especially. Here is an example in notation:

To note, for reasons of ambiguity, many times in music theory there are 2 names for one thing. For example, the note F may sometimes be represented as an E#. Both are harmonically equivalent, but notated differently. For this reason, some of the above intervals also have alternate names. Some are listed below:

m3 = A2 – Augmented second. Augmented simply means one more half step above. So in the case of a M2, which is 2 half steps above the tonic, an Augmented second would be 3 half steps above the tonic.

M3 = d4 – diminished fourth. Similarly, the diminished quality simply means one half step below. So from a P4, the diminished 4th would simply be 4 half steps, as opposed to 5.

P4 = A3 – Augmented third. This is the classic example of an F natural being an equivalent of E sharp.

TT = A4 = d5 – Augmented 4th and diminished 5th are both equivalent to the tritone.