Summary

Description

Chord tones and chord intervals

All chords are based on a certain number of 3rds that are stacked over a root tone. Each one measured from the root, they form the 3rd, 5th, 7th, etc. Each of the stacked 3rds may be raised or lowered to a major/minor/augmented/diminished variant or substitute (e.g. sus4 instead of 3, 6 instead of 7), forming a chord type with its unique character.

In the interval tree above you can see the possible variants/substitutes of each stacked 3rd. They are written the way the intervals are represented in chord names (e.g. m3 instead of b3, dim7 instead of bb7). Each stacked "3rd" (which sometimes isn't really a 3rd anymore because of its variance) can only be represented by one single tone. In oher words: only one variant per branch (e.g. sus2 - m3 - 3 - sus4) can be applied^*.

The major 3rd (3) and perfect 5th (5) are not specifically mentioned in the chord symbol. Consequently the chord symbol for a major chord only consists of the root, written as a capital letter.

Some of the stacked 3rds may be omitted/skipped. The more complex a chord becomes, the more likely the 5th is usually skipped. The minimum requirement is the root and a 3rd (variants sus2, m3, 3 or sus4), which can be considered as a triad with omitted 5th. Or just root and 5th, which is called a "power chord".

*) Examples: If a chord would contain a minor 3rd and a perfect 4th, they cannot be represented as m3 and 4 in the same chord symbol. The 4 would then be considered as an extension 11! If you had a major 3rd (3) and a minor 3rd (m3) in one chord, the major 3rd would be considered as the 3rd while the minor 3rd would be considered as altered tension #9.

Sections of the Chord Symbol

We can break down any chord symbol into a maximum of 5 sections.

1. Root

Usually (but not always) the lowest note of the chord. If the lowest note (the one the bass player would emphasize) is different from the root, it can be notated after a slash at the end of the chord name (5th section).

2. Quality

A letter or icon that stands for a certain type of triad (and, if extended, often implies a certain type of 7th).
No letter or icon means a major triad (or at least a major 3rd, if the 5th is raised to #5 or lowered to b5).

Quality	Triad Type	3rd	5th
m	minor	m3	5 ^*
	major	3	5 ^*
sus2	sus2	2	5 ^*
sus4	sus4	4	5 ^*
dim	diminished	m3	b5
aug	augmented	3	#5

*) if not specified otherwise

You may have noticed, that there are more combinations of 3rds and 5ths. But in those cases the chords are usually reinterpreted, which means a different chord tone is taken as root.

2	m3	3	4	← 3rd 5th ↓
		aug		#5
sus2	m	(major)	sus4	5
	dim			b5

3. Extension Number

Here is a table of possible extension numbers:

b6	Triad + Minor 6th	Ostracized, but actually useful and better readable in line cliches with minor chords like Cm - Cmb6 - Cm6 (correct would be Cm - Abmaj7/C - Cm6)
6	Triad + Major 6th	Triad plus a major 6th, no 7th here!
7	Triad + Minor 7th	Adds a minor 7th to a minor or major triad. Adds a diminished 7th (dim7) to a diminished triad (dim). If you want to add a minor 7th to a diminished triad, the notation is m7b5.
maj7	Triad + Major 7th	Adds a major 7th to a triad.
9	Minor 7th + Major 2nd/9th	Adds a major 2nd/9th to a seventh chord. A minor 7th (7) is included.
maj9	Major 7th + Major 2nd/9th	maj9 = maj7 plus 9. Adds a major 2nd/9th to a chord that includes a major 7th.
11	Minor 7th + Perfect 4th/11th	Adds a perfect 4th/11th to a seventh chord (occurs only in chords with minor 3rd). A minor 7th (7) is included.
13	Minor 7th + Major 6th/13th	Adds a major 6th/13th to a chord that includes a minor 7th. May include a 9 as well (or 11, if if chord has a minor 3rd).
maj13	Major 7th + Major 6th/13th	maj13 = maj7 plus 13. Adds a major 6th/13th to a chord that includes a major 7th. May include a 9 or 11 as well.

4. Alterations and Additions

Altered Tensions

Those are the tensions b9, #9, #11 and b13. V7 (dominant 7th) chords, which resolve to a I chord (with the root a 5th below the root of the V7 chord), are often extended by a b9, #9 and/or b13 to create more tension as with the natural tensions 9 or 13.

Secondary dominants, which derive from chords that have altered tensions by nature (e.g. if IIIm⁷ is changed to III⁷) can also have altered tensions, even if they don't resolve from V to I.

The #11 often extends dominant 7th chords that are not located on the Vth or IIIrd scale degree and where the other (alternatively usable) tensions 9 and 13 would NOT be altered. 9 and #11 are often combined. Maj7 chords can also extended with a #11 if that lydian sound is desired.

Diminished 5th and Augmented 5th

b5 and #5 are enharmonic equivalents to #11 and b13. While in dominant 7th chords #11 and b13 are usually preferable, b5 can most likely be found in m7b5 (half-diminished) chords, and #5 often creates an intended tension in maj7#5 chords. Although not recommended here in most cases, V^7b5 or V^7#5 can be found quite frequently. When improvising you’d most likely use Mixolydian #11 or Harmonic/Melodic Minor 5 (includes b13) over these chords, which indicates that V^7#11 respectively V^7b13 is preferable.

add (add9, add11, etc.)

While the extension number includes a 7th and (theoretically) optionally includes all lower natural tensions (e.g. 13 optionally includes 9 or 11), the litaral add adds the named tension without a 7th and without including other tensions.

omit/no

Not playing a certain chord tone does not necessarily lead to a different (and maybe more complicate) chord symbol. You can name the chord interval (without specifing whether the interval is minor, major, diminished or augmented) with the prefix omit or just no. The least is preferable, if you analyze a played chord, but you don't feel it's necessary to play it that way in general.

Common example: Csus2 can often be seen as C(add9,omit3) respectively C(add9,no3) chord. While notating sus2 can be dangerous, because some musicians might switch to a not intended sus4 chord here. Writing add9no3 is often closer to what it really is, since having the 3rd in the chord doesn’t sound wrong here.

5. Bass (Slash Chord)

Sometimes it seems reasonable to consider a different tone than the lowest as the chords root. That can lead to a cleaner chord symbol or a more comprehensible chord progression. If we still want to have that lowest note as our bass note, we can add it to the chord symbol after a slash. A chord written that way is called a slash chord.

Common examples: G/B or C/E. Progressions: C G/B Am, Fmaj7 C/E Dm7.

Chord name evolution: triad → 7th chord → extended chord

The quality of the basic triad does not change, whatever you add to the chord. But the way the quality is notated in the chord name may change.

Quality Type	Triad notation	with 6th/dim7	with minor 7th	with major 7th
minor triad	m	m6	m7	m^maj7
major triad		6	7	maj7
sus2 triad	sus2	6sus2 6/9(no3)	7sus2	maj7sus2 maj9(no3)
sus4 triad	sus4	6sus4	7sus4	maj7sus4
diminished triad	dim	dim or dim7	m7b5	m^maj7(#11)
augmented triad	aug	aug6	7(#5), aug7	maj7(#5)

While sus2 and sus4 chords are just slighly irregular by switching the position between quality and extension number, the literal dim is replaced by mb5 when adding a minor 7th to it and for aug you'll write a major chord with a #5. To write aug7 respectively +7 is only common with a minor 7th.

The literal dim implies the use of a diminished 7th (dim7). Actually you would write dim as quality for the diminished triad and dim7 in superscript for the diminished 7th. But we only have to write dim once. So dim or dim7 is actually a shorthand notation for dim^dim7.

Summary

Description

Chord tones and chord intervals

Sections of the chord symbol (Shorthand / Lead Sheet notation)

Chord name evolution: triad → 7th chord → extended chord

General Explanations

1. Root

2. Quality

3. Extension Number

4. Alterations and Additions

Altered Tensions

Diminished 5th and Augmented 5th

add (add9, add11, etc.)

omit/no

5. Bass (Slash Chord)

Controls

Possible Chord Names

Warnings

Related Lessons

Tuning

Notation

Chord Names

Letters / Icons

Parentheses

Staves

Save