Diatonic intervals

A diatonic interval is counted between scale degrees within a key. Its number comes from the number of letter names included.

Number first, quality second

C–E is a third because C, D and E are counted. After finding the number, compare semitones to identify major, minor, perfect or another quality.

Practice

• Name both outer notes.
• Count the letter degrees inclusively.
• Play the interval and compare it with a known example.

Start slowly and use your ear to check what you have read.