How Chord Symbols Work

In popular music and jazz, chord symbols (also chord notation or chord shorthand) simplify reading music, especially when the performer has some freedom in chord voicing. (One assumes that if a composer or music director was particular about voicing, the music would be provided in standard notation.) To a newcomer, chord symbols can be confusing because:

• There are generally three separate ways to notate even simple triads.
• Parentheses, superscripts, and subscripts are often applied inconsistently or unnecessarily.
• There are subtleties of meaning (such as the difference between a nine chord and an add nine chord, for example).

Practicing musicians developed chord symbols organically, which helps to explain the notational variations in use. They became widespread in the 20th century. Despite the variation, all chord symbols share the same purpose of abbreviating standard notation. The first step in understanding chord symbols is getting used to the idea that the chord symbol system is based on a set of assumptions designed to make chord symbols as compact as possible. By understanding these assumptions, most chord symbols become transparent and logical. While chord symbols aim to simplify notation, overly verbose symbols can make reading more difficult. It’s important to bear that in mind as chords become complex.

This document should be useful to students, educators, and musicians wishing to expand upon their knowledge of chord symbology, or anyone wanting to resolve the meaning of a chord symbol.

Typically, music students learn chords by stacking major and minor thirds. Others come to know chords by memorizing patterns on a fretboard or a keyboard. Chord symbols, however, are conceptualized on the basis of the relationship between the root note and the other chord tones. In music, the relationship between any two notes is called an interval. Each chord symbol first establishes the root note. The text that follows indicates what intervals occur and which qualities they possess.

In the above examples, the root notes are highlighted in yellow. The type of chord is specified by what follows (or what is implied when the root note stands alone).

An interval—the distance between two notes—consists of a quality and an ordinal number: minor third, for example. The number tells you how many note letters away the second note is (counting the starting note as “one”). So, the distance between a note and itself is a first or unison while adjacent note letters form a second, and so on, up to the eighth or octave, where the starting note letter repeats. From there on, the note letters continue to repeat. For example, a second and a ninth share the same note letter because a ninth is simply a second extended beyond the octave, just as a fourth and eleventh share the same letter, and a sixth and a thirteenth share the same letter. These higher intervals are called compound intervals.

In conjunction with the interval number, the interval quality tells you the distance in half-steps/semitones between the two notes. (“Half-steps” and “semitones” are synonyms and will be used interchangeably for the remainder of this document.) Interval numbers fall into two categories: those which can be perfect (firsts/unisons, fourths, fifths, eighths/octaves, elevenths, and twelfths) and those which can be major or minor (seconds, thirds, sixths, sevenths, ninths, and tenths). We won’t go into why here; it’s far too much to cover. While a deep understanding of intervals helps to tie everything together and is certainly recommended, only a handful of the possibilities are relevant to the chord symbol system. In addition to perfect, major, and minor, any interval number can also be diminished or augmented. Usually we see diminished and augmented with interval numbers that can be perfect. For example, a diminished fifth is lowered by one half-step. Conversely, an augmented fifth is raised by one half-step. “Diminished” and “augmented” are rarely useful to apply to interval numbers that can be major or minor, but one important exception is the chord symbol system. You’ll notice there are two such unusual intervals in the table below: the diminished seventh and the augmented ninth. In such cases, diminished means to lower the note one semitone below minor while augmented means to raise the note one semitone above major.

Importantly, every interval that’s applicable to chord symbols has a default or assumed quality which never needs to be indicated. Only exceptions to the default become part of a chord symbol. Below is a handy cheat-sheet for the intervals relevant to chord symbols, plus the octave, for reference only:

In the table above, you’ll notice that three different interval pairs share the same number of semitones. (Actually, this happens with all intervals, but the table shows only those needed to make sense of chord symbols.) Whenever two intervals are the same number of half-steps apart, they are enharmonically equivalent. That means they are the same pitch but are spelled differently depending on harmonic context. The three enharmonic interval pairs in the table are: the augmented fourth/diminished fifth, the augmented fifth/minor sixth, and the major sixth/diminished seventh. These will be described when their context matters. For now, it’s only important to be aware that enharmonic intervals are possible.

The most fundamental assumption of the chord symbol system is that a root note by itself is a major triad. For example, E♭, F♯, and C are all chord symbols of major triads. By just specifying the root, we are to infer that the chord also includes a major third and a perfect fifth:

Any deviation from the root + major third + perfect fifth formula must become part of the symbol.

A chord is called minor if the third is minor. When speaking of chord symbols, the term minor is reserved for the third alone. As we’ll see, a chord may well include other minor intervals—a minor seventh, ninth, or thirteenth, for example—but, to emphasize the point, if minor is in the name of the chord, it is referring exclusively to the third.

To indicate a minor chord, “min”, a minus sign, or an “m” (always lowercase) is added to the chord symbol. Very occasionally, you might also see “mi”. These mean the third is flattened from its default (i.e., major) value, thus rendering the requisite minor third. The chord symbols E♭min, F♯−, and Cm all represent minor triads:

For the rest of this document, minor chords will interchangeably use the different notations. This will apply to all notational variations once they have been introduced.

Often called power chords within the rock music genre, open fifths have their own unique notation. A “5” is added to the symbol, but, alternatively, it may be noted with “no3”, “omit3”, or “open”. (The use of “5” is the most common in contemporary usage, particularly in rock music genres.) For example, E♭5, F♯no3, C(omit3), and G(open) all represent open fifths:

Parentheses

Flat fifth chords consist of three notes—a root, a major third, and a diminished fifth. (Loosely, they are sometimes called triads even though they don’t fit the traditional definition of triad, a three-note chord that is constructed by stacking major or minor thirds.) To indicate a flat fifth chord, a “♭5” is added to the symbol. In distinction from a power chord, the major third is played. Importantly, the “♭5” should be placed in parentheses so the reader knows that the flat symbol goes with the five and not the root note. For example, B♭5 is a power chord built on B♭ whereas B(♭5) is a flat five chord built on B. Those are very different chords! See the constituents of these and other examples below:

Notice that the “♭5” in B(♭5) means “lower the usual perfect fifth by a semitone”, not “put a flat on whatever note the fifth is”. The perfect fifth of B is F♯, so lowering it by a semitone gives us F♮. We’ll see more of this kind of notation going forward. Remember, the sharp or flat before an interval number always applies to the interval’s default quality, not the note letter. (The note letter may well end up with a flat—as the G does in a C(♭5) chord, for example—but that is coincidence.)

And what about the F♭? Why is that not an E? E and F♭ are enharmonic equivalents and, yes, F♭ is a bit awkward, but an E would be a kind of fourth, not a fifth. Therefore, if we wish to be formal, we must express the fifth as some sort of F.

Augmented triads consist of a root, a major third, and an augmented fifth. To indicate augmented chords, a plus sign, “aug”, or “♯5” is added to the chord symbol. (Once again, when using the “♯5” notation, it is important to use parentheses, so it is clear that the sharp belongs with the 5 instead of the root note. The chord symbols E♭+, F♯aug, and C(♯5) all represent augmented triads:

In the table above, notice that the F♯aug chord contains a C𝄪 (C double sharp). This is the technically correct spelling of an F♯aug chord because only a C (of some sort) can be the fifth of an F (of any sort). C double sharp is enharmonic with D, so, in practice, you may see a D natural on the staff instead of C double sharp. This is done to avoid confusing the performer with a double accidental. In this document, however, the correctly spelled note will always be given in the examples.

Diminished triads consist of a root, a minor third, and a diminished fifth. To indicate diminished chords, a small, raised circle (like a degree symbol), a superscripted lowercase O, or “dim” is added to the chord symbol. Therefore, the chord symbols E♭^o, F♯dim, and C^o all represent diminished triads:

As we saw with F♯aug above, E♭^o results in a double accidental. Just remember that, in practice, you may see simplified enharmonic equivalents written for notes that should technically be spelled with double sharps or double flats. In the case of E♭^o, the B (B double flat) might be written as an A.

On to seventh chords! Stacking a third on top of a triad creates a seventh chord.

As usual, the chord symbol system works by employing assumptions which keep chord symbols compact. In the case of seventh chords, the assumption is that “7” indicates a minor seventh from the root, unless otherwise specified.

A major triad plus a seventh is often called a dominant seventh chord because, in diatonic music, a major chord with a minor seventh occurs only at the dominant scale degree. Hence, D7, for example, is the dominant seventh chord in the keys of G major and G minor. Nevertheless, many musicians will still call it a “D dominant seventh chord”, even when it appears in other keys. This chord might also be pronounced a “D seven” or a “D seventh” chord.

The seven can also be applied to a minor or augmented chord. For example, E♭m7, F♯−7, C+7, and Gaug7 are all chords with a minor seventh added to the voicing:

Remember that minor in the name of E♭m7 continues to apply to the third, not the seventh, even though the seventh is also minor. Similarly, augmented in the name of C+7 applies to the triadic portion of the chord, not the seventh.

The seventh notation can also apply to a diminished chord, but this is a special case! Within the chord name, diminished applies not only to the fifth, but also to the seventh if it is present. For added clarity, one can also call a diminished seventh chord a fully-diminished seventh chord. So, for example, E♭^o7, F♯dim7, and C^o7 mean, add a diminished seventh interval to the already-diminished triad:

Why do we use a diminished seventh instead of a major sixth? Because chords are traditionally built by stacking major or minor thirds. A root plus three minor thirds renders a diminished seventh chord. For the seventh to remain a seventh, it must be a diminished seventh rather than its enharmonic equivalent, a major sixth.

It is still possible, however, to have a diminished triad with a minor seventh. This is called a half-diminished chord, because, in this case, diminished applies only to the chord’s triadic portion. A half-diminished chord is notated with a circle with a line through it. There isn’t a character for this, but often a slashed lowercase O is superscripted like so: ^ø. E♭^ø would be an E flat half-diminished chord. The minor seventh is already implied by the half-diminished symbol, but you’ll sometimes see a “7” added anyway. For example, F♯^ø7 is an F sharp half-diminished chord. A third way to write chords like this is the m7♭5 notation. That’s because a minor seventh chord with a flat fifth works out to be the same as a half-diminished chord. Here are the options:

It is also possible for the chordal seventh to be a major seventh. To indicate this, “maj7”, a triangle (optionally with a redundant 7), or an “M7” (always uppercase) is added to the symbol. Here are some examples:

Note that, in contradiction with other intervals, a ♯ is never used to indicate a raised seventh; that is, a seventh raised from its default of minor. We only refer to major sevenths. In fact, unless you’re talking about simple major triads, major in a chord’s name invariably refers to the seventh. It is possible to have major sevenths with other underlying triads, too. Here are some examples:

Note that the Cdim△ (C diminished major seven) chord is theoretically valid but extremely rare in practice due to its high level of dissonance.

Chord symbols can also represent extended chords, so called because they are derived by continuing to stack thirds beyond the seventh. The first extension is the major ninth. The second is the perfect eleventh. The third and last extension is the major thirteenth. When writing extended chords, you use the number of the highest extension. Formally, all lower extensions, the seventh, and the underlying triad are all part of the chord, though, in practice, some are likely to be dropped. (See the additional explanation below.) Extended chords can include all possible triadic variations. Consider these examples:

Variations are also possible with major sevenths. Consider:

Extended chords are harmonically dense. Consider that, in a thirteenth chord, every note letter is represented! On a standard guitar, it’s not even possible to play seven different notes, yet guitarists do, of course, play thirteenth chords. How? By excluding notes which are formally part of the chord but not necessarily needed to convey the desired quality. When playing from chord symbols, voicing is generally left to the musician, so the choice of what to drop depends on the instrument, the musician, and the musical context. Nevertheless, some intervals are omitted more than others. The fifth is usually the first to go. Lower extensions may also be dropped. Even the root may be dropped if a bass instrument of an ensemble has it covered. The third and the seventh are generally important to the quality of the chord, so they have a strong tendency to remain. But even one of these could be dropped if a singer or lead instrument is playing them as part of the melody. Unaccompanied, however, one can assume that an extended chord should contain at least the root, third, seventh, and the given extension.

As already explained, the ninth and thirteenth are assumed to be major, and the eleventh is assumed to be perfect. However, variations are possible here, too. Besides being major, the ninth can be minor or augmented. The eleventh can be augmented and often is. The thirteenth can be minor. However, the terms minor and augmented already mean other things within chord symbols. To avoid confusion, a flat is used with the extension number to indicate the minor interval while a sharp is used to mean the augmented interval. These are called alterations. In the chord symbol, write the usual triadic portion of the chord followed by the highest unaltered extension, then follow with alterations, usually, but not necessarily, in parentheses. If you have an E♭7 chord with a minor ninth, an augmented eleventh, and a major thirteenth, it would be written E♭13(♭9♯11). An F♯M7 chord with a major ninth and augmented eleventh would be written F♯M9(♯11). Skipping numbers continues to imply the inclusion of the usual intervals. For example, C13(♯11) still implies the inclusion of a major ninth and a minor seventh. If all the extended intervals are altered, the symbol is written as a seventh chord. Consider these examples:

As has already been shown, the fifth can be altered as well. Constructions like those below are also possible. Note that the altered fifth just falls into place with the other alterations.

We’ll move on to sixth chords now, but before we do, it’s important to make a distinction between the notation of jazz and popular music versus classical music. In figured bass (also called thoroughbass), a notation system used primarily in classical music, you might come across something like C⁶. This is used to indicate a C major chord in first inversion. (In figured bass, a note letter with a superscripted 6 indicates that the root is played a sixth above the chordal third, which makes it exactly one octave higher than usual, thus rendering the chord in first inversion.) Figured bass notation is not to be confused with the sixth chords discussed here!

A chord symbol where the root note is immediately followed by a “6” means that a major sixth is added to the chord. The 6 may be used with major, minor, and augmented triads. (With a diminished triad, the major sixth would be enharmonic with a diminished seventh, a chord already described within the system. Therefore, diminished sixth chords are not seen.) Here are valid examples:

It is important to realize that a major sixth and a major thirteenth produce the same note. Why then are there two ways to write that pitch class within a chord symbol? It may be a question of voicing. A composer might notate a sixth chord when the note is meant to be played within the same octave as the fifth. It might also be a way to economize the characters contained in the symbol. As we have seen, a thirteenth chord implies that the chord contains a seventh, ninth, and eleventh as well. There is a way to specify just the thirteenth, and that is the next topic. But it’s not as compact as merely adding a “6”.

Adding a thirteenth (or any other extension) without the seventh or any of the lower extensions is done using the “add” directive. Therefore, Cadd13 means to play a C triad plus the thirteenth, A, without playing the seventh or any of the lower extensions.

The “add” directive can be used with other chord intervals, too. It is compatible with minor and major seconds, perfect and augmented fourths, minor sixths, major sixths when they are included in seventh or extended chords, minor, major, and augmented ninths, perfect and augmented elevenths, and minor and major thirteenths. (That doesn’t mean every possibility is compatible with all the others. Be careful!)

Sixth chords and seventh chords can be combined. You may occasionally see something like D7/6, which is shorthand for D7(add6). Both are valid chord symbols indicating a D dominant seventh chord with an added major sixth. You may also see D7(add13), which likewise means that a B should be added to the chord, but suggests that it should be the B above the chord’s minor seventh, C. Because it says D7(add13) and not D13, the ninth and the eleventh are unambiguously excluded.

Here are some valid examples:

There are other directives besides “add”. We’ve already seen “omit”/“no”. These are interchangeable and used to exclude thirds and fifths. For example:

The final directive is “sus”, which indicates a suspension. A suspended chord usually occurs when a composer delays the resolution of a note of the previous chord to what would ordinarily be the third of the current chord. This isn’t necessarily what’s going on when a suspended chord occurs, but it is the compositional technique from which the chord gets its name. Thus, a suspended chord has no third but does use another note between the root and the fifth instead. That note is usually the perfect fourth, though a major second is often seen as well. Uncommonly, you might see both the second and fourth in suspension. On rare occasions, you might also see a minor second or augmented fourth. Suspended chords are written with a “sus” followed by the suspended interval. If a number indicating the interval is missing, the perfect fourth can be assumed. Here are some simple examples:

Suspended chords aren’t compatible with chord symbol elements that specify a particular kind of third: minor chords, diminished chords, and augmented chords. However, “sus” is compatible with other elements.

The final notational quirk is established for 6/9 chords. These are triads to which a major sixth and major ninth are added, explicitly excluding the seventh. For example:

Many of the chord symbology elements can be combined to describe truly bizarre chords. For example:

Symbols like these are rare. They demonstrate possibilities which are theoretically and syntactically valid but create dissonances so extreme that they may not ever be used in practice. It could be argued that they drive the chord symbol system beyond what’s practical. If you have cause to write such a symbol, explicit notation may well be beneficial.

Normally, with chord symbols, the chord voicing is left to the performer. Still, it is sometimes useful to indicate a particular chord inversion. This can be accomplished with slash notation. The usual chord symbol is followed by a slash and a bass note. For example, C/E is a C major chord in first inversion. C/G is a C major chord in second inversion.

The bass note does not have to be in the chord. An example might be Am/G. How is this different from Am7? It specifically means, play an A minor triad but play a G in the bass. Could it be written Am7/G? Certainly. That would mean, play an A minor seventh chord in third inversion. It amounts to the same pitch classes ringing in the chord, but with an Am/G symbol, the G should only be played in the bass.

The basic rules for slash notation are:

• Only specify a single note after the slash.
• The bass note should not be the root of the chord; that’s redundant.

Thus, G/Am is syntactically invalid. Am/A describes an A minor chord in root position with an A in the bass. For clarity, avoid such redundancies.

Occasionally, one may encounter slash notation with a blank where a chord is expected. For example: Dm /C /B Am. This means, continue to play the D minor chord, but play it with a bass line descending from D to C to B before playing the A minor chord. It is the same as Dm Dm/C Dm/B Am.

There are some practices around chord symbols which are to be avoided.

One practice is to specify a chord symbol with a 2, ♭2, 4, or ♯4 without “sus” or “add”. Consider D4, for example. Without an “add” or “sus”, the meaning is ambiguous. Do you play the third or not? Or is it meant to be an open fourth? It’s anyone’s guess, so don’t do this! Use Dadd4, Dsus4, or Dsus4(omit5) to clearly show your intent.

Some publishers use symbols like Am(sus4). This is syntactically confusing. The fourth may be suspending a minor third—presumably that’s what the symbol is meant to indicate?—but “sus” replaces the third while “m” indicates the third is minor. For clarity, A(sus4) should be preferred since minor cannot apply when the third is absent.

Finally, some publishers use “alt” in a chord symbol to indicate that the chord is altered. For example, G(alt) could mean Gmmaj9(add♯4,6omit5), G7♭9, G7♯11(no3) or any of dozens of other variations. The problem is that the performer has no clue in what way the chord is altered. The publisher may argue that the symbol would be too complex, so the musician should look at the notes. If the notes are provided, this is fine. But on a lead sheet, G(alt) offers no information other than “this chord contains a G”.

It’s easy to create chord symbols that look correct but amount to musical gibberish. Proofreading chord symbols, especially when they’re not just triads, is important. Consider these chord symbols:

Roman numerals are another way to notate chords. This system abstracts chords from their root note and their membership in any particular key by replacing the note letters with roman numerals that indicate scale degree. As such, it is less useful for performance but allows musicians to study and directly compare chord progressions.

Take the chord progression A F♯− D E7 A, for example. It is the same progression as F Dmin B♭ C7 F, just in a different key. The first progression is in the key of A major. It begins on the tonic chord, moves to the submediant chord, moves to the predominant chord, then to the dominant seventh chord, and finally resolves back to the tonic chord. The second progression does the exact same thing, except it’s in F major. If we look at the diatonic triads in these two keys, we see the scale degree of each chord.

Key
A Major	A	B−	C♯−	D	E	F♯−	G♯o
F Major	F	Gmin	Amin	B♭	C	Dmin	Edim

Thus, we simply replace the root note with a Roman numeral that represents each root note’s scale degree. Unfortunately, Roman numeral analysis also suffers from competing notational styles. Depending on which one we use, the example progression becomes either:

Ⅰ ⅵ Ⅳ Ⅴ7 Ⅰ

or

Ⅰ Ⅵm Ⅳ Ⅴ7 Ⅰ

In the former case, we know ⅵ is minor because it’s written in lower case. The latter uses the lowercase “m” that we have seen above. We also see the Arabic numeral “7” added to the Ⅴ chord to indicate that it’s a dominant seventh chord, not just a major triad.

A full discussion of Roman numeral analysis is out-of-scope for this document, but you should be aware that it shares some features with the chord symbols we have seen. Sometimes, it also uses figured bass to show inversions. Additionally, it may use slash notation in an entirely separate way. You might see “Ⅴ/Ⅴ”, for example. This should be read, “the five of five chord”. It means that you take the dominant scale degree, find its dominant, and play that as a dominant chord. For example, in C major, the Ⅴ/Ⅴ chord would be D. (C major’s usual Ⅴ chord is G. If we temporarily treat G as the tonic chord and play G major’s Ⅴ chord, we get D.)

The main point here is that you should be aware that Roman numeral notation exists in at least two forms, that it shares some features with the chord symbols we have seen, but that it can also differ in important ways.

An in-depth discussion of polychords is also out-of-scope for this document, but you should be aware that they exist. Polychords use chord symbols as described in this document, but indicate that two chords should be played at the same time. To distinguish themselves from slash notation, they are written with a horizontal line separating the upper chord from the lower chord. The upper chord is meant to be played above the lower chord in pitch. An example is:

This simply means an F chord should be played above a C chord. Any single chord symbol that includes the constituent notes of both F and C, such as C6add4, Fmaj9, or Am7(add♭6), fails to convey how the chord should be played.

It should now be clear that chord symbols are an efficient shorthand for expressing chords without necessarily requiring traditional notation, and that, by following a set of rules, the chances for ambiguity are eliminated. It should also be clear that, while chord symbols may convey some information on voicing, much of that is left up to the musician reading the notation.