Play C, then F, then G, then C. You have played a chord progression. In Roman-numeral shorthand: I-IV-V-I. It sounds finished because the last chord answers the tension the middle two set up.

The seven diatonic chords

Every major key gives you seven chords, built by stacking thirds on each degree of the scale. In C major:

• I = C major (C E G)
• ii = D minor (D F A)
• iii = E minor (E G B)
• IV = F major (F A C)
• V = G major (G B D)
• vi = A minor (A C E)
• vii° = B diminished (B D F)

Uppercase Roman numerals mark major chords; lowercase mark minor; the ring after vii marks diminished.

Functional groups

The seven chords fall into three functional groups:

• Tonic function: I, iii, vi. Home. Rest.
• Predominant function: ii, IV. Motion away from home.
• Dominant function: V, vii°. Tension pulling back to tonic.

The four workhorses

Four progressions carry most of Western pop, folk, and hymn writing:

1. I-V-vi-IV: Let It Be, Don’t Stop Believing, hundreds more. Sits in three adjacent segments of the circle of fifths.
2. vi-IV-I-V: same set, rotated. The Zombie shape.
3. ii-V-I: the jazz cadence. In C major: Dm7 to G7 to Cmaj7.
4. I-IV-V-I: the blues shell, the folk shell, the hymn shell. The simplest possible T-PD-D-T.

Inversions, briefly

A chord played with a note other than the root in the bass is inverted. C major played as E-G-C is first inversion (marked I⁶). Same three notes, different bass note, softer landing. Songwriters use inversions to smooth the bass line between two chords whose roots would otherwise leap.

Try the tool

The chord progression generator plays every preset in every key and lets you build custom Roman-numeral strings. Best paired with the circle of fifths.