What Is a Chord Progression? The Four Chords Behind Countless Songs
A chord progression is the sequence of chords a piece of music moves through, in order and in time. The most famous one in pop music is C, G, A minor, F, usually one chord per bar and repeated, written in numbers as I–V–vi–IV. A progression is the harmony under a song: the melody sits on top of it, and the same progression can carry many different melodies.
What does a chord progression look like?
On a chord chart, a progression is a row of chord symbols between bar lines:
| C | G | Am | F |
Each chord lasts one bar here, and the four bars repeat. Anyone with a guitar or a keyboard can play along from that line alone. The chart tells you which chord and when; it does not tell you the melody, the rhythm of the strumming or how to arrange the notes. If you are not sure what a chord is, start with What Is a Chord in Music?
Why are chord progressions written in Roman numerals?
Roman numerals describe a progression without tying it to one key. Each numeral is the position of the chord’s root in the key’s scale: I is the chord on the first note, V the chord on the fifth. Uppercase means a major chord, lowercase a minor one.
That makes one formula playable in every key:
| Key | I | V | vi | IV |
|---|---|---|---|---|
| C major | C | G | Am | F |
| G major | G | D | Em | C |
| D major | D | A | Bm | G |
| A major | A | E | F♯m | D |
| E major | E | B | C♯m | A |
Five rows, one progression. A singer who needs it lower or higher changes the row, not the song. The harmonic field lesson shows where the seven chords of a key and their numerals come from.
What are the four chords behind so many songs?
The four chords are I, V, vi and IV, the major chords on the first, fifth and fourth notes of a major key and the minor chord on the sixth. Played in that order, they are the loop behind a long list of hits from different decades:
- “With or Without You” (U2): D, A, Bm, G, I–V–vi–IV in D major.
- “Don’t Stop Believin’” (Journey): the opening piano part is E, B, C♯m, A, I–V–vi–IV in E major.
- “Someone Like You” (Adele): A, E, F♯m, D, I–V–vi–IV in A major.
The comedy group The Axis of Awesome built a whole medley, “4 Chords”, out of songs that use this loop.
Start the same four chords from the vi and you get vi–IV–I–V, which sounds darker because it begins on the minor chord. “Zombie” (The Cranberries) loops E minor, C, G and D, the same four chords as I–V–vi–IV in G major, entered at a different point. Why the loop works so well, function by function, is the subject of the lesson The Progressions Everyone Uses.
What other chord progressions are common?
A handful of progressions turn up again and again:
| Progression | Numerals | In C major | A well-known example |
|---|---|---|---|
| Three-chord rock and roll | I–IV–V | C F G | “La Bamba” |
| The 1950s progression | I–vi–IV–V | C Am F G | “Every Breath You Take” (The Police) |
| Twelve-bar blues | I, IV and V over twelve bars | C, F, G | “Johnny B. Goode” (Chuck Berry) |
| The jazz cadence | ii–V–I | Dm G C | “Autumn Leaves” opens with one |
| Pachelbel’s Canon | I–V–vi–iii–IV–I–IV–V | C G Am Em F C F G | Pachelbel’s Canon in D |
The examples are in their own keys; the numerals are the same in any key.
Why do so many songs use the same chords?
Because a major key only has seven chords, and three of them do most of the work. The chord on I sounds like home, the chord on V pulls back towards it, and the chord on IV moves away from home without that pull. Most progressions are ways of leaving home and coming back, and there are only so many short routes. The lesson on what the degrees do explains those three jobs, and why the chords on ii, iii and vi can stand in for them.
That is also why a common progression does not make songs sound alike. Melody, rhythm, tempo, arrangement and words carry most of what makes a song recognisable.
How do you find the chord progression of a song?
Find the key first, then follow the bass, then decide major or minor for each chord. Because a key has only seven chords, most songs only need you to choose among I, IV, V and vi. The step-by-step method is in How to Figure Out the Chords of a Song by Ear, and the first step has its own article, How to Find the Key of a Song by Ear.
How do you write your own chord progression?
- Pick a key. C major is the easiest on a keyboard, G major on a guitar.
- List its chords. In C major: C, Dm, Em, F, G, Am, and B diminished, which you can skip at first.
- Start on I. It tells the listener where home is.
- Move away with IV, ii or vi. These leave home without sounding urgent.
- Build tension with V. It is the chord that most wants to go home.
- End on I, or loop. V–I sounds finished. Ending a loop on V sends it round again.
C–Am–F–G and C–F–G–C both follow these steps. Play each a few times, then change one chord and listen to what changes.
Try it
Hearing a progression is a different skill from reading one. The lesson The Progressions Everyone Uses plays progressions such as I–V–vi–IV and ii–V–I with the last chord missing and asks you to supply it. After that, Reading a Progression puts the whole method together on progressions you have not seen before.