12-Bar Blues Chords
The 12-bar blues is the most-played form in popular music, and it runs on just three chords — but with a twist: they're all dominant seventh chords. In C that's C7, F7 and G7.
The 12-bar pattern
Twelve bars, three lines of four. Counting each bar as one chord:
Line 1: C7 · C7 · C7 · C7
Line 2: F7 · F7 · C7 · C7
Line 3: G7 · F7 · C7 · G7
That last bar — the turnaround — lands on G7, the dominant, which throws you straight back to the top for another chorus.
Why a 7th on every chord?
In classic harmony only the V is a dominant 7th. The blues breaks that rule on purpose, stacking a flatted 7th on I, IV and V alike. The result is a chord that never fully resolves — perpetually leaning forward — which is exactly the restless, soulful feeling the blues is after. Compare a clean C major triad with C7 and you can hear the grit the added B♭ brings.
In any key
Move the pattern to any root using the dominant sevenths library. In G it's G7 – C7 – D7.
Practice it for real
Chord Rush drills dominant 7ths in every key so your blues changes become automatic.
Frequently asked questions
What chords are in a 12-bar blues in C?
A 12-bar blues in C uses three chords: C7 (the I), F7 (the IV) and G7 (the V) — all dominant seventh chords. The dominant 7th on every chord is what gives the blues its gritty, unresolved flavor.
What is the 12-bar blues chord pattern?
The standard pattern is: I–I–I–I / IV–IV–I–I / V–IV–I–V. In C that is C7 C7 C7 C7 / F7 F7 C7 C7 / G7 F7 C7 G7. The final V (the "turnaround") sends you back to the top.
Why does the blues use dominant 7th chords on every degree?
In traditional harmony only the V chord is dominant, but the blues makes I, IV and V all dominant 7ths. That deliberate "wrongness" — a flatted 7th over every chord — is the sound of the blues, echoing the blue notes of the blues scale.