Triads and Chord Formulas

A chord is defined as three or more notes played together.

A triad — as the name implies — is a three-note chord.

This post will cover how to construct the various triads and provide examples for each type of chord.

It will also provide common fingerings for each type of chord, along with instruction on how to play them on a guitar with any root note.

Chord Formulas

A chord formula is a numerical formula based on the major scale that tells us which notes are included in any given chord.

Each note in a major scale is given a number, which is called a degree or scale step, indicating its position in the scale.

In a C major scale (fig.1):

  • C is the first degree or scale step.
  • D is the second degree or scale step.
  • E is the third degree or scale step.
  • F is the fourth degree or scale step.
  • G is the fifth degree or scale step.
  • A is the sixth degree or scale step.
  • B is the seventh degree or scale step.

Fig.1

Each type of chord (major, minor, diminished and augmented) has its own formula that indicates which notes in the major scale are included in the chord.

Triads

There are four primary types of triads — major, minor, diminished and augmented — each with its own chord formula.

Major Chords

The chord formula for a major chord is: 1, 3, 5.

A major chord contains the first, third and fifth degrees of the major scale with the same root note.

For example, a C (or C major) chord contains the notes C, E and G — the first, third and fifth notes in a C major scale (fig. 2a).

Major chords are notated with their root note (the note that names the chord). They have a bright quality about them.

Minor Chords

The chord formula for a minor chord is: 1, b3, 5.

A minor chord contains the first, flatted (or lowered) third and fifth degrees of the major scale with the same root note.

A Cm (or C minor) chord contains the notes C, Eb and G — the first, flatted third and fifth notes in a C major scale (fig.2b).

So the difference between a major chord and a minor chord is that the major chord contains the third note in the major scale and the minor chord contains the flatted (or lowered) third note.

Minor chords are notated with a lowercase m after the root note. They have a dark quality about them.

Diminished Chords

The chord formula for a diminished chord is: 1, b3, b5.

A diminished chord contains the first, flatted third and flatted fifth degrees of the major scale with the same root note.

A C° (or C diminished) chord contains the notes C, Eb and Gb — the first, flatted third and flatted fifth notes in a C major scale (fig.3c).

Diminished chords are notated with a small circle to the right, and near the top of, the root note. They sound tense and have an unsettled quality about them .

Augmented Chords

The chord formula for an augmented chord is: 1, 3, #5.

An augmented chord contains the first, third and sharped (or raised) fifth degrees of the major scale with the same root note.

A C+ (or C augmented) chord contains of the notes C, E and G# — the first, third and sharped fifth notes in a C major scale (fig.2d).

Augmented chords are notated with a small plus (+) symbol to the right of the root note. They have a suspenseful quality about them.

Fig.2

Triads Based on a D Major Scale

All of the chords in the examples above had C root notes, so the chord formulas were based on a C major scale.

We will now look at the same chord types with D root notes, whose formulas are based on a D major scale.

In a D major scale (fig.3):

  • D is the first degree or scale step.
  • E is the second degree or scale step.
  • F# is the third degree or scale step.
  • G is the fourth degree or scale step.
  • A is the fifth degree or scale step.
  • B is the sixth degree or scale step.
  • C# is the seventh degree or scale step.

Fig.3

D (or D Major) Chord

The chord formula for a major chord is 1, 3, 5.

A major chord contains the first, third and fifth degrees of the major scale with the same root note.

A D chord contains the notes D, F# and A — the first, third and fifth notes in a D major scale (fig.4a).

Dm (or D Minor) Chord

The chord formula for a minor chord is 1, b3, 5.

A minor chord contains the first, flatted third and fifth degrees of the major scale with the same root note.

A Dm chord contains the notes D, F and A — the first, flatted third and fifth notes in a D major scale (fig.4b).

Note: When you lower (or flat) a sharp note (an F# in our example) by a half step, it becomes a natural note (an F natural in our example).

D° (or D Diminished) Chord

The chord formula for a diminished chord is 1, b3, b5.

A diminished chord contains the first, flatted third and flatted fifth degrees of the major scale with the same root note.

A D° chord contains the notes D, F and Ab — the first, flatted third and flatted fifth notes in a D major scale (fig.4c).

D+ (or D Augmented) Chord

The chord formula for an augmented chord is 1, 3, #5.

An augmented chord contains the first, third and sharped fifth degrees of the major scale with the same root note.

A D+ chord contains the notes D, F# and A# — the first, third and sharped fifth notes in a D major scale (fig.4d).

Fig.4

Rules for Raising and Lowering Chord Tones

All of the major scales other than a C major scale contain one or more sharp or flat notes. And some of those notes will inevitably have to be raised or lowered to build chords according to their formulas.

The following principles will assist us in raising and lowering notes:

  • When you lower a sharp note a half step, it becomes a natural note.
  • When you lower a natural note a half step, it becomes a flat note.
  • When you lower a flat note a half step, it becomes a double flatted note.
  • When you raise a flat note a half step, it becomes a natural note.
  • When you raise a natural note a half step, it becomes a sharp note.
  • When you raise a sharp note a half step, it becomes a double sharp note.

Summary of Triad Formulas

The four triad formulas covered in this post are summarized below:

  • Major chord: 1, 3, 5.
  • Minor chord: 1, b3, 5.
  • Diminished chord: 1, b3, b5.
  • Augmented chord: 1, 3, #5.

Triads Based on All 12 Root Notes

The major, minor, diminished and augmented chords based on all 12 root notes are shown in fig.5.

Fig.5

Triads on a Guitar

Major Chords

A common fingering for a major chord is shown in fig.6.

Fig.6

This fingering will allow you to play a major chord with any root note:

  • To play a C major chord, place your third finger on the C on the third string, fifth fret (fig.7a).
  • To play a D major chord, place your third finger on the D on the third string, seventh fret (fig.7b).

Fig.7

Minor Chords

A common fingering for a minor chord is shown in fig.8

Fig.8

This fingering will allow you to play a minor chord with any root note:

  • To play a Cm chord, place your third finger on the C on the third string, fifth fret (fig.9a).
  • To play a Dm chord, place your third finger on the D on the third string, seventh fret (fig.9b).

Fig.9

Diminished Chords

A common fingering for a diminished chord is shown in fig.10

Fig.10

This fingering will allow you to play a diminished chord with any root note:

  • To play a C° chord, place your fourth finger on the C on the third string, fifth fret (fig.11a).
  • To play a D° chord, place your fourth finger on the D on the third string, seventh fret (fig.11b).

Fig.11

Augmented Chords

A common fingering for an augmented chord is shown in fig.12.

Fig.12

This fingering will allow you to play an augmented chord with any root note:

  • To play a C+ chord, place your second finger on the C on the third string, fifth fret (fig.13a).
  • To play a D+ chord, place your second finger on the D on the third string, seventh fret (fig.13b).

Fig.13

Triad Voicings

There are numerous ways to play a triad on a guitar and you should become familiar with as many of them as possible. Triads can be played as open chords, barre chords or on any set of three strings.

Regardless of how you play a triad, it will contain the notes indicated by the formulas covered in this post.

Related Links

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