How to Build a Bassline from a Chord Chart

Sooner or later someone hands you a chord chart: a row of chord names, a few bar lines, and no bass part at all. That is normal. Most charts are written for the whole band, and the bass player is trusted to work out a line. You can do that with three notes per chord and one idea for joining the chords together.

Everything here is for a four-string bass in standard tuning, E A D G from the thickest string to the thinnest. The tab is laid out the way our guide to reading bass tab describes, and each bar has four beats.

What the chart is telling you

Each chord symbol starts with a letter, and that letter is the root. Under a G chord the root is G. Under Em the root is E. The small m means the chord is minor, which changes the chord's third and leaves the root where it is. A 7 after the letter works the same way: G7 still has G at the bottom.

Two more things to look for. Bar lines show how long each chord lasts, and unless the chart says otherwise, one chord fills one bar. A slash chord such as D/F♯ is a D chord with F♯ as its lowest note, and the lowest note is yours, so play the note after the slash.

The example for the rest of this article is four bars, one chord in each: G, D, Em, C.

Start with the roots

Find each root on the E or A string, play it on beat one, and let it ring for the whole bar.

   G            D            Em           C
G|------------|------------|------------|------------|
D|------------|------------|------------|------------|
A|------------|5-----------|7-----------|3-----------|
E|3-----------|------------|------------|------------|

That is G at the 3rd fret of the E string, then D, E and C at the 5th, 7th and 3rd frets of the A string. Play it round a few times with a click or a drum beat. It is already a bassline, and plenty of songs ask for nothing more. If finding those four notes took some counting, learning the note names on the neck will speed this step up more than anything else.

Add the fifth and the octave

Two more notes sit close to every root, in shapes that never change. "Higher" here means toward the thinner strings.

• The fifth is one string higher and two frets up. From G at the 3rd fret of the E string, that is D at the 5th fret of the A string.
• The octave is two strings higher and two frets up. From the same G, that is the G at the 5th fret of the D string.

Fret the root with your index finger and the other two notes fall under your ring finger or pinky. The shapes work for major and minor chords alike, because both kinds of chord have the same root and fifth. Diminished and augmented chords have a different fifth, so when you meet one, stay on the root until you have learned its shape.

Here is the progression again with root, fifth, octave, fifth in every bar, one note per beat:

   G            D            Em           C
G|------------|------7-----|------9-----|------5-----|
D|------5-----|---7-----7--|---9-----9--|---5-----5--|
A|---5-----5--|5-----------|7-----------|3-----------|
E|3-----------|------------|------------|------------|

Your hand makes the same shape four times and only the starting fret moves. Say the notes as you play them. The G bar is G, D, G, D. The D bar is D, A, D, A. The Em bar is E, B, E, B, and the C bar is C, G, C, G.

Lead into the next chord

That line outlines each chord, but it treats every bar as a separate box. An approach note joins the boxes together. On beat four, in place of the second fifth, play a note right next to the root of the chord that is coming. The ear hears the change a beat before it arrives.

A half step below the new root gives the strongest pull. A whole step above or below also works when that note belongs to the key.

   G            D            Em           C
G|------------|------7-----|------9-----|------5-----|
D|------5-----|---7--------|---9--------|---5--------|
A|---5-----4--|5--------9--|7--------5--|3-----------|
E|3-----------|------------|------------|---------2--|

Take it one bar at a time. The G bar ends on C♯, the 4th fret of the A string, a half step below D. The D bar ends on F♯ at the 9th fret of the A string, a whole step above E. The Em bar ends on D at the 5th fret of the A string, a whole step above C. The C bar ends on F♯ at the 2nd fret of the E string, a half step below G, which carries you back to the top.

Three of those four notes belong to the key of G major. The C♯ does not, and it still sounds right, because it lasts one beat and moves straight to the note it was pointing at. That is the working rule for approach notes: keep them short and land on the root. Our walking bass starter guide takes the same idea further.

Then choose a rhythm

A chart rarely tells you the rhythm either. For that, listen to the kick drum and to the song. The same notes can be four even quarter notes, as written above. They can be the root held for two beats with the fifth and the octave after it. Or you can drop back to the root alone and play it in steady eighth notes. Try the fuller line in the chorus and plain roots in the verse, and hear which the song wants. Often the plainest version is the right one.

Practice it against the changes

A line like this only settles when the chords are moving underneath you. Have a guitarist or pianist loop the four chords, or record them yourself, and play each version of the line over the top: roots, then the root-fifth-octave shape, then the approach notes.

Lazy Lopez: Bass can be the band for this. Its Progressions tool plays common chord changes with a full rhythm section, and the pop I-V-vi-IV in its library gives you these same four chords when the key is set to G. A badge follows the live chord as the band plays, and you can switch from Full band to Click when you want to be the only bass in the room. If your chart is not in the library, Build a progression lets you stack your own chords and have each one last one, two or four bars. The app is free, with no account and no ads.