Think of an interval as a musical distance between two notes. The term just means, if you play one note, then some other note on a piano (or any instrument), how far did you go from the first note to the second note? So if you take a piano and press down a random key, then press the key immediately to the right of it, that's a short musical distance. But if you start on that same key, and then skip over 5 keys, and then play the next one, that's a bigger interval. So an interval is just a way of measuring how far apart notes are in music.

We'll start off by going over three intervals first just to get started on other ideas and then cover all of them later. There's nothing complicated about other intervals, but intervals are really simple, and we just need to learn the names of these 3 to get going:

  1. Octaves
  2. Half Steps
  3. Whole Steps

In Western Music, there's really only 12 notes. That might sound weird. But technically once you play through 12 keys on a piano, after that you're just starting over in a higher octave. The next key up from there is considered to be the same note you started on, but just in a higher octave. Just so you can hear this. Try this example.

f
f#
g
g#
a
a#
b
c
c#
d
d#
e
f
Try playing F followed by the  F below it

Obviously, you can hear a difference between them. One is higher in pitch. But They should sound very much the same in an inexplicable sort of way also. The reason it sounds like the "same note" even though it's not exactly the same, is that the note in the higher octave is twice the frequency of the note in the lower octave (or at least close enough to twice). So they just I'm sort of vibe together in a really special way. I'm hoping to add more on that whole topic later.

You can do this with other notes, just play the same note and then the one below it. It is the same note, but a higher pitch. That's and octave.

The smallest distance between two pitches is called a half step. A half step is the musical distance from one key on a piano to the key next to it. It doesn't matter which key you start from. An interval is the distance between the pitches.

c
c#
d
d#
e
f
f#
g
g#
a
a#
b
c
To hear what this interval sounds like, play the Efollowed by the F
c
c#
d
d#
e
f
f#
g
g#
a
a#
b
c
You can start from any note and play the next closest note up or down to make a half step interval. D, for instance, is a half step away from D#

A whole step is another interval which is a little bigger than a half step. Basically, you just skip a note in between. So, for instance, if you go from G to A, that's a whole step. Notice that you skip over a note to make this interval (in this case that note would be G#). Here's some more examples.

c
c#
d
d#
e
f
f#
g
g#
a
a#
b
c
E to F#
c
c#
d
d#
e
f
f#
g
g#
a
a#
b
c
C# to D#

There's a lot more intervals that we'll talk about later, but you can probably imagine how to create them by extrapolating from what we did here. Plus making sense of the names for them is easier once you know about scales and chords. Half steps and whole steps are all you need to start learning scales, so we'll start with the most foundational scale of all, the Major Scale.

I'll also just add the names for all the other intervals at the bottom here, to not keep you in suspense, but the names of them will make sense later, so don't worry.