Intervals, Chords and Harmony

Harmony is the vertical dimension of music: how pitches sound together. It begins with intervals, builds into chords, and organizes those chords into progressions that create momentum. This lesson gives you the vocabulary to describe harmony precisely.

Intervals: quantity and quality

An interval is the distance between two pitches. We describe it with a number (its quantity) and a quality. The number counts letter names inclusively, so C up to E is a third because it spans C, D, E. The quality—major, minor, perfect, augmented, or diminished—specifies the exact size in semitones. Unisons, fourths, fifths, and octaves come in perfect, augmented, and diminished forms, while seconds, thirds, sixths, and sevenths come in major and minor forms. A major third spans four semitones; a minor third s