Jam Jam
Reading a progression in scale degrees (Roman numerals)
Each Roman numeral names the chord built on a degree of the scale: I on the tonic, IV on the fourth note, V on the fifth. Upper case marks a major chord, lower case a minor chord (ii, iii, vi), and a small circle a diminished chord (vii°). In C major, I = C, ii = Dm, iii = Em, IV = F, V = G, vi = Am. Writing in degrees lets you play the same progression in any key.
Major-key chord progressions: I-V-vi-IV, I-vi-IV-V, ii-V-I
Four four-chord patterns come back across a very large share of pop, rock and songwriting: I-V-vi-IV, its rotation vi-IV-I-V, I-vi-IV-V (often called the 50s progression) and I-IV-V-I, the oldest of all. In jazz, ii-V-I (with seventh chords) is the basic move. The chart gives them in five keys that are easy on guitar.
| Degrees | In C | In G | In D | In A | In F |
|---|---|---|---|---|---|
| I–V–vi–IV | C G Am F | G D Em C | D A Bm G | A E F♯m D | F C Dm B♭ |
| I–vi–IV–V | C Am F G | G Em C D | D Bm G A | A F♯m D E | F Dm B♭ C |
| vi–IV–I–V | Am F C G | Em C G D | Bm G D A | F♯m D A E | Dm B♭ F C |
| I–IV–V–I | C F G C | G C D G | D G A D | A D E A | F B♭ C F |
| ii7–V7–Imaj7 | Dm7 G7 Cmaj7 | Am7 D7 Gmaj7 | Em7 A7 Dmaj7 | Bm7 E7 Amaj7 | Gm7 C7 Fmaj7 |
The 12-bar blues
The 12-bar blues uses only three chords, usually sevenths: I7 for four bars, IV7 for two, I7 for two, then V7, IV7, I7 and V7, which turns the form around. There are many variants (IV7 in bar 2, the last V7 replaced by I7 at the end of a song). The chart below gives the most widespread form in four common blues keys.
| Bar | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Degrees | I7 | I7 | I7 | I7 | IV7 | IV7 | I7 | I7 | V7 | IV7 | I7 | V7 |
| In A | A7 | A7 | A7 | A7 | D7 | D7 | A7 | A7 | E7 | D7 | A7 | E7 |
| In E | E7 | E7 | E7 | E7 | A7 | A7 | E7 | E7 | B7 | A7 | E7 | B7 |
| In G | G7 | G7 | G7 | G7 | C7 | C7 | G7 | G7 | D7 | C7 | G7 | D7 |
| In C | C7 | C7 | C7 | C7 | F7 | F7 | C7 | C7 | G7 | F7 | C7 | G7 |
Most widespread form; bar 12 (V7) turns the form around, and becomes I7 to finish.
Minor-key chord progressions: i-VII-VI-VII, i-iv-v
In minor, the degrees change: i, iv and v are minor, III, VI and VII major. The descending i-VII-VI-VII (in A minor: Am G F G) is everywhere in rock and film music, i-VI-III-VII in current pop. The minor v is often replaced by a major V7, borrowed from the harmonic minor scale, for a stronger pull back to i.
| Degrees | In Am | In Em | In Dm | In Bm |
|---|---|---|---|---|
| i–VII–VI–VII | Am G F G | Em D C D | Dm C B♭ C | Bm A G A |
| i–iv–v–i | Am Dm Em Am | Em Am Bm Em | Dm Gm Am Dm | Bm Em F♯m Bm |
| i–VI–III–VII | Am F C G | Em C G D | Dm B♭ F C | Bm G D A |
| i–iv–V7–i | Am Dm E7 Am | Em Am B7 Em | Dm Gm A7 Dm | Bm Em F♯7 Bm |
Playing and transposing progressions with Jam Jam
The Jam Jam mobile app ships 100 ready-to-play progressions and a progression generator that suggests the next chord, in beta and on mobile only. On the web, the songbook (free, with an account) transposes a chord chart to the key you choose, the chord catalogue shows their diagrams and the online keyboard lets you play them.
To understand why these chords belong together, read our guide to the circle of fifths.
Frequently asked questions about chord progressions
What is the most common chord progression?
I-V-vi-IV (in C: C G Am F) and its rotation vi-IV-I-V are among the most frequent in pop. I-IV-V and the 12-bar blues dominate rock and blues, ii-V-I jazz.
What does I-V-vi-IV mean?
It is the chords on degrees 1, 5, 6 and 4 of the major scale: in G major, G D Em C; in D, D A Bm G. The lower-case vi marks a minor chord.
What chords are in a blues in A?
A7, D7 and E7. The most common form: A7 for four bars, D7 for two, A7 for two, then E7, D7, A7, E7.
How do I transpose a progression to another key?
Write it in degrees, then replace each degree with the matching chord in the new key. The progression chart does it for five keys, and the Jam Jam songbook transposes a whole chord chart in one move.
Look up the diagram of every chord in your progression in Jam Jam’s free chord catalogue.