When you play 2 different notes at the same time or one after the other, you will have a lower and a higher note. This means there is a distance (in pitch) between the 2 notes. This distance is called the interval between the 2 notes, the note interval, or simply interval.
You can measure this intervals between notes in number of semitones, and this takes us directly to our first interval: the semitone.
The easiest way to explain semitones is to look at the piano keyboard. A semitone is the interval from a key on the keyboard to the first note at the left or the right. So, for example, the interval from C to C# (or Db) in the next figure is a semitone.
Or, for example from G# (or Ab) to A:
It’s also possible to have a semitone between 2 white keys; this is the case between E and F and between B and C:
Notice that it’s not possible to have an interval of a semitone between 2 black keys on the piano.
Other names for a semitone are: half tone or half step.
The whole tone
The whole tone, or also called whole step, is an interval that consists of 2 semitones. Here are some examples of a whole tone:
From C to D:
From F# (or Gb) to G# (or Ab):
From E to F# (or Gb):
From Bb (or A#) to C:
The minor third
The minor third is an interval of 3 semitones, or a whole tone and a half tone (semitone).
From C to Eb:
From A to C:
From F# to A:
From Bb to Db:
The major third
The major third is an interval of 4 semitones, or 2 whole tones.
From C to E:
From Eb to G:
From A to C#:
From F# to A#:
The perfect fourth
The perfect fourth (very often simply called fourth) is an interval of 5 semitones (or 2 whole tones and a semitone).
From C to F:
From F to Bb:
From Eb to Ab:
From A# to D#:
The tritone is an interval of 6 semitones or 3 whole tones (that’s why it’s called tritone, since ‘tri’ means three).
From C to F#:
From Ab to D:
The perfect fifth
The perfect fifth (very often simply called fifth) is an interval of 7 semitones (or 3 whole tones and a semitone).
From C to G:
From A to E:
From Eb to Bb:
From F# to C#:
The minor sixth
The minor sixth interval consists of 8 semitones, or 4 whole tones.
From C to Ab:
From F# to D:
The major sixth
The major sixth interval consists of 9 semitones, or 4 whole tones and a half tone.
From C to A:
From Eb to C:
The minor seventh
The minor seventh is an interval of 10 semitones, or 5 whole tones.
From C to Bb:
From F# to E:
The major seventh
The major 7th is an interval of 11 semitones, or 5 whole tones and a half tone.
From C to B:
From Gb to F:
The perfect octave
The perfect octave (mostly just simply called octave) is an interval of 12 semitones, or 6 whole tones.
Since there are 12 different notes in Western music, this means that when you go up an octave, you arrive at the same note. Well, it’s of course not exactly the same note, since it’s higher in pitch: an octave higher.
For example, from C to C:
Or, from Ab to Ab:
The perfect unison
We haven’t mentioned yet the simplest of all intervals: the perfect unison, mostly simply called unison.
The unison is the interval between a note and itself, so 0 semitones. Now, that sounds a bit strange and it’s actually not really an interval in the real sense of the word.
When, for example, a piano and a trumpet play the same note at the same time, you can say that they play in unison. I don’t think I have to give an example on the piano keyboard 🙂
It might seem like a terrible task to memorize all the intervals with their names, but perhaps the next scheme based on the scale of C major might help to have a better overview of the intervals. The names of the intervals indicated above the keys of the keyboard are the intervals from the low C (indicated with the red 1) to that note. Compare the name of the interval with the number of the note in the C major scale (in red, under the keyboard):
Below a complete overview of all the intervals with even other alternative names (source: Wikipedia):
Note names in a scale
A note in a scale is often named after the interval it makes with the root note.
What I mean is, for example when we are in the key of C, that the E is called the major 3rd, the Eb the minor 3rd, the F the 4th, the G the 5th, the A the 6th, the B the major 7th and the Bb the minor 7th.
The 2nd note (D in the case of the key of C) however, is not called after its intervals with the root. You could call the 2nd note just the 2nd. The Db would then be the minor 2nd. There is however another name for the 2nd, I will talk about that in another lesson.
There are still some more notes: the Gb is the flattened 5th (or short: the b5). F#, which is the same note, would be the sharpened 4th (#4).
The Ab is a flattened 6 (b6). The same note, the G# is the sharpened (or augmented) 5th (#5).
You will often see even other notes like the 9th, the 11th etcetera. I will treat those in another lesson.
It’s very practical to be able to quickly recognize intervals. For that reason, I advice to do the exercises below.