Chord Name Decoder Ring

In this lesson, I attempt to demystify chord names. By understanding the five possible parts of a chord name and how to decode them, you can decipher any chord chart without looking things up in a reference. The follow-up lesson, Creating Chord Voicings with Barre and Shell Chords, shows how to recreate any chord on the fly without looking it up.

To check your work while the rules are still new, try the Chord Name Decoder — a free tool that takes any chord name apart into the same five parts and spells out the notes it asks for.

Chord name decoder ring

Chord names can sometimes seem like a secret language, but decoding them is a useful skill that isn’t that difficult once you understand the rules. And when you understand how chords are constructed, you won’t need to rely on chord books or online diagrams to find voicings. Instead, you’ll be able to create your own and tailor them to your playing style.

In this lesson, we’ll break down chord names into five component parts and show how each part has a logical set of rules that translates directly into the intervals that make up the chord.

At the end, we’ll pull all this together into a reference table that shows the recipe for every commonly-used chord type.

Intervals

Semitone distance	Interval symbol	Interval name
0	R	root
1	♭2 / ♭9	Minor second
2	2 / 9	Major second
3	♭3	Minor third
4	3	Major third
5	4 / 11	Perfect fourth
6	♭5 / #11	Tritone / Diminished fifth / Augmented fourth
7	5	Perfect Fifth
8	#5 / ♭6	Minor sixth / Augmented fifth
9	6 / ♭♭7	Major sixth / Diminished seventh
10	♭7	Minor seventh
11	7	Major seventh

The 12 intervals used to create all chords.

This lesson assumes a basic familiarity with intervals. In the context of a chord, an interval is the distance in semitones from the chord’s root upward to a specific chord tone. A specific semitone distance can have more than one name (i.e., interval names sometimes have enharmonic equivalents), but this table shows the most common names for each interval as used in chord construction. If any of this so far is unfamiliar, check out my YouTube video Intervals: Guitar’s “secret decoder ring” for a refresher.

The five components of chord names

Chord names consist of up to five components, in the following order:

1. The root name (e.g., A♭, C#, E)
2. Third-type qualifier (e.g., m, sus2, sus4)
3. Seventh-type qualifier (e.g., 6, 7, dim7, maj7)
4. Altered notes (e.g., add 9, add11, add13, ♭5, #9, #11)
5. Slash notation (e.g., C/G)

The only required component is the root name. The other elements are optional, and can appear in many combinations, but they almost always appear in the order presented here. For example, A♭m(maj7)#11/E♭ is a valid (albeit highly unusual) chord name.

Here are a few examples with brief explanations of their components:

Chord name	Root name	3rd-type	7th-type	Altered notes	Slash notation
C	C	major	None	None	None
G7	G	major	♭7	None	None
A♭m7	A♭	minor	♭7	None	None
D/F#	D	major	None	None	F# in the bass
Fmadd9	F	minor	None	Added 9th (G)	None
A♭m(maj7)#11/E♭	A♭	minor	Major 7	Added #11 (D)	E♭ in the bass

Example chord names decoded

Three-note chords: triads and sus chords

The baseline chord against which all other three-note chords are measured is the major triad, which consists of a root, major third, and perfect fifth.

There are five ways that a major triad can be altered in practice by modifying either the major third, the perfect fifth, or both:

1. Lowering the third by one semitone yields a minor triad.
2. Lowering both the third and the fifth by one semitone yields a diminished triad.
3. Raising the fifth by one semitone yields an augmented triad.
4. Replacing the third with a major second yields a suspended 2nd chord.
5. Replacing it with a perfect fourth yields a suspended 4th chord.

Chord type	Third-type qualifier	Interval spelling	Examples
Major triad	(None)	R-3-5	C
Minor triad	m, min, -	R-♭3-5	Cm, Cmin, C-
Augmented triad	aug (or +)	R-3-#5	Caug, C+
Diminished triad	dim, °	R-♭3-♭5	Cdim, C°
Suspended 2nd	sus2	R-2-5	Csus2
Suspended 4th	sus4	R-4-5	Csus4

Three-note chords

Notice that each chord type has a unique chord-type qualifier. A major triad adds nothing to the root name, but the other chord types each add their own modifier.

Four-note chords: 6th and 7th chords

There are two common types of four-note chords. Seventh chords add a major, minor, or diminished seventh interval to a triad, and sixth chords add a major sixth (which is the same interval as a diminished seventh).

The 7th-type qualifier is added after the 3rd-type qualifier, and some combinations of qualifiers are not used in practice. For example, suspended chords do not typically have an added 6th or 7th.

Chord type	3rd+7th qualifier	7th qualifier	Interval spelling	Examples
Dominant 7	7	7	R-3-5-♭7	C7
Major 7	maj7, Δ	maj7, Δ	R-3-5-7	Cmaj7, C Δ
Minor 7	m7, min7, -7	7	R-♭3-5-♭7	Cm7, Cmin7, C-7
Minor-major 7	m(maj7)	(maj7)	R-♭3-5-7	Cm(maj7)
Diminished 7	dim7, °7	7	R-♭3-♭5-♭♭7	Cdim7, C °7
Half-diminished	m7♭5	7	R-♭3-♭5-♭7	Cm7♭5
Major 6	6	6	1-3-5-6	C6
Minor 6	m6	6	1-♭3-5-6	Cm6

Common four-note chords

The most commonly used chords here are the dominant 7, the major 7, and the minor 7. They are well worth committing to memory, but you’ll come across the others relatively infrequently.

When practicing these chords, it is worth considering families of voicings. If you start with a Dominant 7 voicing, you can raise the 7th to create a major 7th chord—or lower the third to create a minor 7th chord. If you lower the third and the fifth, you’ve created a half-diminished (m7♭5) chord. I’ll go into more depth on this (with plenty of examples) in a future lesson.

Extensions and “add” chords: 9s, 11s, and 13s, oh my!

Dominant chords are often extended to create richer harmonies. A 9th chord takes a dominant 7 chord and adds a major 2nd (called the 9th in this context). Upper extensions are given higher numbers because they are usually played more than an octave above the root, but that isn’t a requirement. To convert an upper interval back down to the more commonly-known intervals, just subtract 7 from the number, so a 9th becomes a 2nd, an 11th becomes a 4th, and a 13th becomes a 6th.

An 11th chord takes a 9th chord and adds a perfect 4th (called the 11th). A 13th chord takes an 11th chord and adds a major 6th (called the 13th). A 13th chord contains 7 notes — every single note of the Mixolydian mode! In these chords, the 5th is often omitted, and the lower extensions can sometimes be omitted as well. After all, it’s impossible to play a 7-note chord on a 6-string guitar, these complex multi-note voicings can get muddy quickly.

An “add” chord takes a base chord and adds a specific note to it. For example, a Cadd9 chord takes a C major triad and adds a major second to it. A Dm(add11) takes a D minor triad and adds a perfect fourth to it. It’s rare to see add13 chords, because the most common ones are just called 6 chords. By far, the most common “add” chord is add9.

Altered notes

The fourth potential part of a chord name is the addition of altered notes. These will take the form of a sharp or flat combined with an interval name. The most common altered notes are the ♭5, #9, and #11.

A Gm7♭5 is a G minor triad with a flat seven and with the fifth lowered one half-step. This is all captured in the chord’s name based on the rules we’ve seen so far.

E7#9 (sometimes called the “Hendrix” chord) is an E major triad with a flat seven and an augmented second. An augmented second is the same interval as a minor third, but since there’s already a major third in the chord, we can’t call it a third.

Slash chords

Slash chords have nothing to do with the acclaimed Guns ’n Roses lead guitarist. They are simply a way of specifying which note is played on the lowest string of the voicing. C/G is a C major triad with G in the bass.

Slash notation can be added to any kind of chord. Some players assume that the note after the slash must always be part of the chord, but this is not necessarily true. Slash chords are primarily used to indicate bass notes, which may or may not be part of the chord base chord.

Another common misunderstanding is that slash chords imply complex structures, but they are often used to simplify harmonic transitions, for example enabling a smooth walkdown in the bass from G→D/F#→Em.

Reference: Interval spellings of common chord types

To help solidify your understanding, here’s a table summarizing the interval spellings of most common chord types. You can use this table to check your understanding, or as a handy reference for decoding any chord name into its interval components.

Interval spellings of common chord types

I hope this lesson has helped you better understand how chord names are constructed. With this foundation, you can start identifying the components of any chord and even create your own voicings. In a future lesson, I’ll show you how to put this knowledge into practice on the fretboard, enabling you to play any chord without referring to a chord book or online diagram.