The Four-Chord Loop
Play the I–V–vi–IV progression behind hundreds of pop hits, switch keys with one click, and learn why these four chords work so well together.
Four chords, hundreds of hit songs. Press play — you have heard this loop your whole life.
A progression is a journey
Inside a key, chords get roman numerals: I is built on the first note of the scale, V on the fifth, and so on. Uppercase means major, lowercase (like vi) means minor. I is home — the most stable place in the key. A chord progression is a round trip: leave home, build expectation, get pulled back. I–V–vi–IV does exactly that, four bars at a time.
Why these four?
I, IV, and V are the three strongest major chords in the key, built on the strongest bass roots. vi is the one splash of minor — same neighborhood, dimmer light. A solid home, a strong pull, a touch of shade, and a warm road back: the four pieces fit.
Same loop, any key
Use the key picker above and switch keys. The notes change, but the relationships do not — roman numerals describe relationships, not fixed pitches. That is why this loop works in every key: same magic, different height.
Reorder the chords
Same four chords, starting from vi instead: vi–IV–I–V. The very first beat lands on the minor chord, and the whole loop turns moodier.
Quiz
In roman-numeral land, which chord is "home"?