The 12-Bar Blues Form

The most common form of the blues is a 12-bar pattern of chord changes. That is, a repeated twelve-bar chord progression. This is called “12-Bar Blues”.

You should remember a bar is the same as a measure. Most often in blues you will count 4 beats to each bar – 4/4 time.

In a blues song this 12-bar cycle gets repeated over and over through the course of the tune. A blues song might play through it 20 times. It will depend on the specific song.

The blues can be played in any key. In whatever key you are in, 12-bar blues uses the same basic sequence of I, IV, and V chords. It is most easily thought of as three 4-bar sections – the first 4, the middle 4, and the last 4 bars.

The first 4 bars just use the I chord - I, I, I, I.

The middle 4 bars go IV, IV, I, I.

And the last 4 bars go V, IV, I, V. Then you repeat the whole thing again.

So, the basic 12-bar sequence looks like this:


The blues form - I-I-I-I-IV-IV-I-I-V-IV-I-V
The blues form - I-I-I-I-IV-IV-I-I-V-IV-I-V