I–IV–V–I

PAC (IV-V-I progression in C, in four part harmony )

IV-V7-I in C, on guitar.

In music, I–IV–V–I or IV-V-I is a common chord progression and cadence that, "unequivocally defines the point of origin and the total system, the key."

Composers often begin pieces with this progression as an exposition of the tonality:

I-IV-V-I in Bach's WTC II, Prelude in C Major.

I-IV-V-I in Handel's Suite in F♯ Minor, Prelude.

It may be viewed as an abbreviated circle progression:

I-IV-               V-I = I–IV–V–I 

I-IV-V-I in Scarlatti's Sonata in D Minor, K. 517.

"Along with motion toward the fifth (V), IV [the subdominant] appears as a corrective, depriving V (the dominant) of its independence and pointing it back in the direction of its origin [I]." In the key of C, IV provides the note F♮ and eliminates the possibility of G major, which requires F♯. The progression is also often used at the end of works and sections.

See also

• Predominant chord
• Three-chord song
• V–IV–I turnaround
• ii–V–I turnaround
• Ragtime progression