Interval

An interval is the difference in pitch between two notes — in other words, how far apart they are. Intervals are what give melodies their shape and chords their sound.

We describe intervals in two ways: by their size (how many notes apart they are) and their quality (which gives them their specific sound, like major, minor, diminished, or augmented).

For example, the interval between C and E is called a major third. It's called a “third” because it spans three scale degrees (C, D, E — scale degrees 1 to 3), and it's “major” because the notes are four half steps apart, giving it a bright, consonant sound.

Intervals are measured in half steps (also called semitones) — the smallest distance between two notes on a piano. A half step is the distance from one key to the very next (black or white). Two half steps make a whole step.

The pattern of intervals in the major scale is what gives each scale degree — and the chords built from them — their unique sound and function.

Below is a table summarizing the intervals up to an octave with the first note starting on a C on the piano.

Interval	# Half-steps	Piano
Minor Second	1
Major Second	2
Minor Third	3
Major Third	4
Perfect Fourth	5
Tritone	6
Perfect Fifth	7
Minor Sixth	8
Major Sixth	9
Minor Seventh	10
Major Seventh	11
Octave	12