Roman numerals in one minute
Numerals describe a chord's position in the key, so a progression works in any key: I is the chord built on the first note, IV on the fourth, V on the fifth. Upper case is major and lower case is minor.
| Key | I | ii | iii | IV | V | vi |
|---|---|---|---|---|---|---|
| C | C | Dm | Em | F | G | Am |
| G | G | Am | Bm | C | D | Em |
| D | D | Em | F♯m | G | A | Bm |
| A | A | Bm | C♯m | D | E | F♯m |
| E | E | F♯m | G♯m | A | B | C♯m |
The most common chord progressions
| Progression | In G | In C | Sound |
|---|---|---|---|
| I → V → vi → IV | G D Em C | C G Am F | The modern pop progression |
| I → IV → V | G C D | C F G | Rock, folk and country |
| vi → IV → I → V | Em C G D | Am F C G | The pop progression starting on the minor: emotional ballads |
| I → vi → IV → V | G Em C D | C Am F G | The 1950s progression |
| ii → V → I | Am D G | Dm G C | The core of jazz harmony |
The 12 bar blues
Twelve bars using only I, IV and V: four bars of I, two of IV, two of I, then V, IV, I and V to turn around to the top. In A:
| Bars 1 to 4 | Bars 5 to 8 | Bars 9 to 12 |
|---|---|---|
| A · A · A · A | D · D · A · A | E · D · A · E |
How to use them
- Choose a key that suits the voice, and use a capo to move the open shapes: a capo on the 2nd fret turns G, C and D shapes into A, D and E.
- Change the strumming pattern to change the mood. See strumming patterns.
- Write songs by changing the order, the rhythm or one chord of a familiar progression.
The circle of fifths shows these chord families at a glance.