I’m sure you’ve come across chords like sus2, sus4, maj7, etc. But what do these names mean? You’ll be happy to know these names aren’t randomly assigned, but are derived from the quality of the chord. In this lesson we look at chord formula basics to help make sense of these names and build an understanding of how chords are made.
What is a Chord Formula?
A chord formula is list of intervals which makes up a chord. Therefore, understanding what its formula is saying requires a bit knowledge about intervals. If you’re not familiar with guitar intervals, I recommend reading Intervals on Guitar: The Most Important Music Concept for Guitar Players? to get up to speed.
Importance of Learning Chord Formulas
What if I tell you a Gadd9 chord consists of the notes G-B-D-A? Great, you know what a Gadd9 chord is. Now, what if I tell you a Gadd9 chord is built from the formula 1-3-5-9? This is more useful. You’re not limited to just knowing what a Gadd9 chord is. You can now build any add9 chord because they have the same chord formula.
Chords are built using the major scale, which is a diatonic scale. The intervals, notes, and quality of a chord are relative to the major scale.
Chord Formulas for Common Chords
Below are the chord formulas for common chord types. These formulas remain the same regardless of the root note.
Major chords consist of the root, major 3rd, and perfect 5th. Its formula is 1-3-5.
Minor chords have a flattened 3rd, making it a minor third. The minor chord formula is 1-♭3-5.
Major 7th Chords
The formula for the major 7th chord is 1-3-5-7.
Minor 7th Chords
The minor 7th chord formula is 1-♭3-5-♭7.
Dominant 7th Chords
The dominant 7th chord is similar to a major 7 chord, but with a flattened 7th. It’s formula is 1-3-5-♭7.
9th chords consist of 5 notes because they also include the 7th.
Major 9th Chord
The major 9th formula is 1-3-5-7-9. Because of fingering on the guitar, the 5th is left out.
Minor 9th Chord
The minor 9th formula is 1-♭3-5-7-9.
Unlike 9th chords that retain the 7th interval, add9 chords do not. The 9th is simply added to the chord formula.
Major add9 (add9)
The major add9 formula is 1-3-5-9.
Minor add9 (madd9)
The minor add9 formula is 1-♭3-5-9.
The suspended 2nd chord removes the 3rd and replaces it with the 2nd. It’s chord formula is 1-2-5.
Sus4 chords are similar to sus2 chords, but the 3rd is replaced with a 4th instead. It’s chord formula is 1-4-5.
At this point you should understand what a chord formula is and how its used to build chords. This also should help strengthen your understanding of the link between scales and chords. In future lessons we’ll take a look at how to apply this knowledge to playing scales over chords to create more interesting sounding guitar solos.