What are Chords?
A chord is any combination of 3 or more notes played simultaneously e.g. strummed on the guitar. While technically any set of three or more notes can be defined as a chord, usually, a chord is a series of notes taken from a scale.
How are chords named?
Chords are named by the letter assigned to the chord and the chord type or chord quality. We’ll discuss chord type and chord quality shortly, but when it comes to the letter assigned to the chord this is determined by the root note.
Root Notes
The root note of a chord defines the tonal centre of the chord. It is the lowest note letter included within a chord. For example, A major consists of the notes A, C#, and E. A, being the lowest note, is, therefore, the root note of the chord. This is the same regardless of whether the chord is major, minor, or another chord quality.
How Chords Are Built
There are 12 notes available in music. When assembled in order these 12 notes form the chromatic scale, the parent scale for all other scales.
| A | A# | B | C | C# | D | D# | E | F | F# | G | G# |
The Chromatic Scale
Think of the chromatic scale the same way an artist might consider a pallet containing every available color. The artist wouldn’t normally use every available color, instead opting for color combinations that work well together taken from the full range of available colors.
If you want to read more about scales, notes, including natural and accidental notes (flats, and sharps), and basic guitar theory I’ve written more here, but in simple terms, scales are just sets of notes taken from the chromatic scale and then assembled in ascending or descending order. Chords are simply sets of notes taken from an accompanying scale.
The diagram below demonstrates this.
As you can see, the A major scale in the example above contains 7 notes taken from the chromatic scale beginning on A. The A major chord contains three notes taken from the A major scale. The key to understanding how chords are built is to know the formula for the notes included within a chord.
Scale Degree Formulas
Chords can be assembled directly from the chromatic scale, but it’s far more common to construct scales from the major scale using scale degree formulas. We do this by assigning numbers to the individual notes of the major scale called scale degrees.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| A | B | C# | D | E | F# | G# |
In the example above A is the first scale degree, C# is the third scale degree, and E is the 5th scale degree. The scale degree formula for building A major therefore is 1, 3, 5.
Because the major scale degrees are assigned the numbers 1 – 7 the major scale is the ‘master scale‘ and is typically used as a reference for other scales and chords.
For example, the natural minor scale’s 3rd, 5th, and 7th scale degrees are flattened by one note, compared to the major scale. As the major scale is the ‘master scale’ the minor scale degrees are therefore written relative to the major scale using flats (b) or in other cases sharps (#) to describe whether the note is higher or lower in pitch when compared to the major scale.
| 1 | 2 | b3 | 4 | 5 | b6 | b7 |
| A | B | C | D | E | F | G |
Below are scale degree formulas for the most common chord qualities (e.g. major, minor, augmented, or diminished ~ If you don’t know what these terms mean yet don’t worry, we’re about to explain)
| Chord Quality | Scale Degree Formula | Chord Symbol (key of A) |
| Major | 1, 3, 5 | Amaj (or simply A) |
| Minor | 1, b3, 5 | Amin |
| suspended | 1, 4, 5 | Asus |
| Augmented | 1, 3, #5 | A+ |
| Diminished | 1, b3, b5 | A° |
| Dominant 7th | 1, 3, 5, b7 | A7 |
| Major 7th | 1, 3, 5, b7 | Amaj7 |
| Minor 7th | 1, b3, 5, b7 | Amin7 |
Types of Chords and Chord Qualities
Chord Type
When discussing chord types, although often used interchangeably to describe a chord’s quality, we are mostly referring to the construction of the chord in terms of the number of notes included which defines the complexity of the chord.
The first chords taught on guitar are simple 3 note triads. These are the major and minor chords.
Triads contain 3 notes comprised of thirds. A third is a type of interval we’ll discuss further along, but in simple terms triads include the first three notes of the major scale, skipping every second note.
Tetrads (4-note chords) are also built by stacking thirds (chords built using thirds are referred to as tertian chords) and are more harmonically complex than triads, as they contain an additional note. A 7th chord is a Tetrad because it contains the notes included in a triad plus an additional 7th.
Extended chords are also built by stacking thirds, but additionally, contain notes beyond the 7th scale degree. You might be wondering how this is possible considering the major scale contains 7 scale degrees.
Well, once extending past the 7th scale degree we encounter the next highest octave, and instead of beginning at 1 again, we continue counting. So, including an additional third above a 7th chord gives us a 9th, which builds an add9 chord, adding an additional third again would give us an add11 chord, and an additional third again gives us an add13 chord.
As you can see extended chords can include 5 or more notes, however, often the additional notes from the next highest octave replace the 5th or 7th, making the chord easier to play.
Another type of harmony often referred to as a chord type is a dyad. These contain just two notes. The most common dyads are power chords, which are built from the 1st and 5th scale degrees of the major scale. While technically not chords in the strictest sense of the word (they contain less than 3 notes) power chords are referred to as chords for all intents and purposes.
As you can see, the most common chords are built by stacking thirds. Each of the examples above begins with a root note, which is the foundation for the chord. The number of thirds added to the root, therefore, defines the chord type.
Chord Quality
If discussing chord types in terms of harmonic complexity e.g. the number of notes included, it’s best to think of a chord’s quality as its flavor or mood.
This can start to delve into grey territory which I’ll explain shortly, but when discussing triads there are 4 qualities of chord available, each with its own distinctive mood:
- Major – Cheerful, happy
- Minor – Dark, sad
- Diminished – Dramatic, suspenseful
- Augmented – Mysterious, unstable
Things get a little murkier when discussing tetrads and extended chord types. For example, a dominant 7th chord is a combination of major and minor and as a result has a distinct mood that differs from the four listed above. If just getting started learning chords on the guitar, this isn’t practical, so for now I’d suggest focusing on triads.
A chord’s quality is defined by the intervals that make up the chord. An interval is simply the distance between 2 notes. We’ll discuss intervals next, but for now, it helps to understand there are 4 qualities of triad available and for every one of these, there are 12 chords available, as each note of the major scale can be the root note of a chord.
Intervals
As mentioned intervals describe the distance between two notes. This can be melodic (e.g. the notes are played sequentially) or harmonic (e.g. played simultaneously).
The simplest way to understand the interval type is to count the number of natural notes (including the first and last note) between two notes. For example, if we count from A to C we count three notes in total (including both A and C), therefore the interval is a third.
But, there’s more to intervals, as just like chords, intervals have qualities. For example, if we increase C in pitch by one note to C# the interval is referred to as a major third.
The table below shows each of the 12 available intervals.
| Interval Name | Abbreviated Name | Notes Between |
| Unison | P1 | 0 |
| Minor 2nd | m2 | 1 |
| Major 2nd (Diminished third) | M2 | 2 |
| Minor 3rd (Augmented second) | m3 | 3 |
| Major 3rd (Diminished fourth) | M3 | 4 |
| Perfect 4th (Augmented third) | p4 | 5 |
| Diminished fifth / Augmented fourth | D5 / A4 | 6 |
| Perfect 5th (Diminished sixth) | p5 | 7 |
| Minor 6th (Augmented fifth) | m6 | 8 |
| Major 6th (Diminished seventh) | M6 | 9 |
| Minor 7th (Augmented sixth) | m7 | 10 |
| Major 7th | M7 | 11 |
| Perfect Octave | P8 | 12 |
As you can see unisons, fourths, fifths, and octaves are perfect, diminished, or augmented, they cannot be major or minor.
Seconds, thirds, sixths, and sevenths are always major or minor. The difference between the two comes down to the fact that when we reduce and increase a minor interval by one note the interval is major, or when reducing in pitch a major interval the interval becomes minor.
When we reduce a perfect or minor interval the interval is referred to as diminished. When a perfect or major interval is raised by one note it is augmented.
Aside from the intervals listed above we also commonly describe the relative distance between 2 adjacent notes as a semitone (aka halftone), or three notes a tone (aka whole tone).
What’s the difference between major and minor chords?
Combinations of the interval types listed above determine a chord’s quality. For example, a major chord consists of a root note, a major third, and a perfect fifth.
A minor chord contains a root note, a minor third, and a perfect fifth. The third determines if a chord is major or minor.
Alternatively, when discussing diminished chords, we are essentially stacking two minor thirds on top of each other (relatively speaking). For example, diminished chords (diminished means to lower or reduce) consist of a root note, minor third, and diminished 5th. Augmented chords on the other hand consist of a root note, major third, and augmented fifth.
As you may have guessed, we can therefore build chords using intervals or scale degree formulas. Below is a table showing the intervals used to build the 4 types of triad discussed earlier.
| Quality | Intervals |
| Major (Maj) | Root / Major third (M3) / Perfect fifth (P5) |
| Minor (min) | Root / minor third (m3) / Perfect fifth (P5) |
| Augmented (+ or aug) | Root / Major third (M3) / Augmented Fifth (Aug5) |
| Diminished (o or dim) | Root / minor third (m3) / Diminished fifth (dim5 |
