12-Bar Blues Chords in Every Key

The Three Blues Chords

A 12-bar blues uses three chords: the I7, IV7 and V7 of the key. In A that's A7, D7 and E7. In E it's E7, A7 and B7. The IV sits five semitones above the key note and the V sits seven.

They always fall in the same twelve bars:

Pick your key below to see that form with real chord names and the fingering for each one — or jump to the all-keys chart.

Pick a Key

When any of the three chords is a fretted shape, the shortcut box shows the lowest capo position that turns all three into open-string shapes at the same pitch. That's the move most players make at a jam, and it's the same arithmetic as the guitar capo chart.

12-Bar Blues Chords in All 12 Keys

The full chart: I7, IV7 and V7 for every key, and the easiest way to play each one on guitar.

Only 4 keys keep an open string in all three chords — D, E, G, A. Every other blues is a capo away from one of them, and none of them needs more than capo 4.

The Form, Bar by Bar

Twelve bars, three lines of four. Each line does a job:

• Bars 1–4 set up home. Four bars of I — or I, IV, I, I with a quick change.
• Bars 5–8 move away and come back. Two bars of IV, then two of I. In a sung blues this is where the first line repeats.
• Bars 9–12 resolve. V, then IV, then I, then V again to turn the form around and start over.

Two variations come up all the time. The quick change moves to IV in bar 2 and straight back — if the bass goes somewhere in the second bar, that's what's happening. And the ending: bar 12 is V while the form repeats, but on the last chorus it stays on I so the song can stop. Some older blues also stay on V through bar 10 instead of dropping to IV; listen for it on the first pass.

Use the toggles in the key picker above to hear these in your head as you read them — the chords change, the bar count never does.

Work Out the Blues in Any Key

No chart to hand? Five steps, using B♭ as the example:

1. 1Find the I chord. It is the key’s own note with a 7 on it. A blues in B♭ starts on B♭7.
2. 2Count up five semitones for the IV chord. From B♭: B, C, D♭, D, E♭. The IV chord is E♭7.
3. 3Count up two more semitones for the V chord. From E♭: E, F. The V chord is F7 — seven semitones above the key note.
4. 4Drop the three chords into the form. Four bars of I, two of IV, two of I, then one bar each of V, IV, I and V. For a quick change, play IV in bar 2.
5. 5Choose shapes your hands can play. If any of the three chords is a fretted shape, capo up from the nearest open blues key below. Capo 1 with A7, D7 and E7 shapes sounds as B♭7, E♭7 and F7.

The counting works the same in every key because the blues is built on intervals, not letters. If the semitone counting is new, basic guitar keys for beginners walks through how keys and their chords fit together.

When the Band Calls B♭

Guitarists learn the blues in E and A. Sax and trumpet players learn it in B♭, F and E♭, because those are the keys that sit well on their instruments. Every jam session eventually puts the two groups on one stage.

Here's an A blues, transposed up one semitone by the same code that runs the TransposeChord transposer:

| A7 | A7 | A7 | A7 |
| D7 | D7 | A7 | A7 |
| E7 | D7 | A7 | E7 |

| Bb7 | Bb7 | Bb7 | Bb7 |
| Eb7 | Eb7 | Bb7 | Bb7 |
| F7 | Eb7 | Bb7 | F7 |

You now have two ways to play it. Read the right-hand chart as written, with B♭7, E♭7 and F7 as fretted shapes. Or put a capo on fret 1, read the left-hand chart, and let the capo do the transposing — same pitch, open strings.

The capo is the faster fix when you're standing on stage. The transposed chart is the one to hand the bass player, who doesn't have a capo.

Blues Questions, Answered