I–V–vi–IV Chord Progression
The pop progression. Its loop of major and minor chords sits under a huge share of modern pop songs.
I–V–vi–IV in every key
The numerals stay the same in every key; only the chord names change. The easiest keys on guitar are G major, C major, A major.
Songs that use I–V–vi–IV
Questions
What chords are in the I–V–vi–IV progression?
In C major it is C, G, Am and F. In any other key, use the same numbered steps (I – V – vi – IV) of that key's scale.
What is the easiest key for I–V–vi–IV on guitar?
G major, C major and A major use open chords, so they are the easiest places to start.