What is a Cadential 6/4?

A cadential 6/4 is a specific chord progression used in tonal harmony that appears just before a cadence, typically leading into the dominant chord. Although it looks like a tonic chord in second inversion, it actually functions as a decorative expansion of the dominant harmony rather than as a true tonic chord.

The name “6/4” refers to the intervals formed above the bass note. In this chord, the bass note is the fifth scale degree, and the other two notes form intervals of a sixth and a fourth above the bass. For example, in the key of C major, the cadential 6/4 chord contains the notes G–C–E, with G in the bass.

In practice, the cadential 6/4 typically resolves to a dominant chord (V) before finally resolving to the tonic (I). The upper notes (the 6 and 4 above the bass) usually move down by step to become the fifth and third of the dominant chord, creating a strong sense of tension and release at the cadence. This progression is commonly written as I⁶⁄₄ → V → I and is frequently used in classical and tonal music to strengthen the final resolution of a phrase.