Intervals by Number (Counting Distance)
Measuring the distance between two notes by counting letter names — a 2nd, a 3rd, a 5th, and so on.
Explainer
An interval is the distance between two notes, measured by counting letter names.
Include the starting note when you count. C up to E is a 3rd: C(1) D(2) E(3).
C up to G is a 5th: C D E F G — five letter names.
The size of an interval is just this number for now — 2nd, 3rd, 4th, 5th, 6th, 7th, or octave (8th). Later grades add detail about each interval's exact quality.
Worked examples
Example 1
C to E is a 3rd
C(1) D(2) E(3) — three letter names.
Example 2
C to G is a 5th
C D E F G — five letter names.
Example 3
Counting a 6th
C to A: C D E F G A — six letter names, a 6th.