C, C- (Cm, Cmin), Co (Cdim), C+
C7, CΔ7 (CM7, Cmaj7), C-7 (Cm7, Cmin7), Cø7 (C-7b5, Cm7b5), Co7, CmΔ7 (C-Δ7, CminMaj7, C-maj7), C7b5, C+7 (C7#5), CΔ7b5, CΔ7#5, C-7#5 (or Abadd9/C, see Slash chords, below)
C6, Cadd9 (C(add9)), C69, C-add9 (C-(add9), Cmin add9), C-6 (Cmin6, Cm6), C-69 (Cmin69, Cm69), Csus (Csus4), C2 (Csus2), C5, C7sus
9th is major unless otherwise specified; 7th is almost always assumed to be present, and is minor unless otherwise specified; C9, C7b9, C7#9, CΔ9 (CM9, Cmaj9) (b9 and #9 rarely occur on M7 chord), C-9 (Cm9, Cmin9) (b9 rarely occurs, #9 is same as b3), C-Δ9 (CminMaj9, CminM9, etc.) (b9 rarely occurs, #9 is same as b3), C-9b5 (b9 rarely occurs, #9 is same as b3), any of the aforementioned 9th chords could have an altered 5th, such as C9b5, CΔ9#5, etc., Co9 (fairly rarely seen but quite possible, might equally be notated D7b9/C--see Slash chords, below), (Co7b9 is rarely used, #9 would be same as b3)
11th is assumed to be perfect unless explicitly sharped; 7th and 9th are almost always assumed to be present, 7th is assumed minor unless otherwise specified, 9th is assumed major unless otherwise specified; C11 (usually no 3rd, considered same as C9sus), C-11 (3rd is present, distinguishing it from C9sus or C11), CΔ11 (rarely used, but possible), C7#11 (C9#11), CΔ7#11 (CΔ9#11), C-7#11 (C-9#11), Cø11 or C-11b5 (C-7#11b5 is redundant and is not used; #11 implies that the perfect 5th is present), indeed any of the aforementioned 11th chords could have an altered 5th and/or and altered 9th, such as C11b5b9, CΔ9#11#5, etc., but redundant spellings should be avoided (so not C7#11b5, and not C-11#9), Co11 is theoretically possible but might more likely be written F13b9/C (see Slash chords, below)
13th is assumed to be major unless explicitly flatted; 7th and 9th are assumed to be present, minor 7th and major 9th unless otherwise specified; 11th is assumed not to be present and must be specified; C13, CΔ13, Cm-13, a b13 is usually written with a 7 or 9 followed by the b13 as in C7b13 or C9b13 (b13 is most commonly used with a dominant 7th chord, and is less commonly used with a Δ7 or a -7 chord), any 13th chord may have an altered 5th and/or altered 9th and/or altered or unaltered 11th which is usually notated after the 13 as in C13b5b9 or CΔ13#11 or C13#9#11, note that the b13 implies that a perfect 5th or flatted 5th or no fifth is present in the chord (thus C7b13 or C7#5, depending on the function of the Ab/G#, but not C7#5b13 which would be redundant)
When a chord is not in root position the bass note should be provided after a slash, such as C7/E or C7/G or C/Bb (notice that the 7 is not strictly needed in the last example, because it's stated in the bass); the slash can also be useful for describing a chord in which the musical context implies that the bass note is best considered separately from the chord above it such as C/F (if F is a pedal tone, or simply easier than writing FMaj9(no 3rd)) or if the bass note seems to be unrelated to the rest of the chord, as in C7sus/Gb
When a chord cannot be sensibly defined with any single chord designation, and/or is best defined as the combination of two simpler chords, the two chords can be stacked vertically with a horizontal line between them. This is distinct from a "slash chord", which is a chord over a single separate bass note; in a polychord both elements in the symbol represent entire chords. For example, the polychord Ab7|A7 is simpler and clearer than A13Δ7#9#11, especially if the context implies two separate chords. [The two chords should be stacked vertically with a horizontal line between, rather than as shown here.]
Some systems of jazz chord notation put all altered notes in parentheses, as in CΔ7(#5) or C7(b9)(b13). This seems unnecessary because the altered note is an integral part of the chord. However, when some unusual comment is needed for a chord to be accurately noted, parentheses may be the most direct way, as in CΔ9(no 5) or C11(with 3rd).
When the typography permits, the Arabic extension numbers and the flats and sharps that modify them are usually printed as superscripts (small raised numbers) rather than full-sized as shown here. Commonly they're also stacked vertically when there's more than one. [I'm too lazy to do any of that here.]
This page was last modified October 28, 2014.
Christopher Dobrian, firstname.lastname@example.org