2 Interval quality

The quality of an interval is its distinctive sound, based on the number of half steps between the two pitches. The terms used to label interval quality are:  major, minor, perfect, diminished and augmented.

The interval sizes 2, 3, 6, and 7 use the qualifiers Augmented, Major, minor, or diminished.  The interval sizes 1, 4, 5, and 8 use the qualifiers Augmented, Perfect, or diminished. As a given interval increases in size by a half step, you go up in the chart to determine the correct qualifier. If a given interval is made smaller by a half step, you go down in the chart to determine the correct qualifier.

For example, if a major 3rd (M3) is made smaller by a half step, the resulting interval would be a minor 3rd (m3). If a perfect 4th (P4) is made larger by a half step, it becomes an augmented 4th (A4). Study the following chart:

int_qualitya int_qualityb
 Check yourself: