Chord Symbols Explained: Major, Minor, Seventh and Slash Chords
A chord symbol names the root, the quality, the extra notes and the bass. Here is how to read Cmaj7, C7, Cm7, C/E and C7b9, and the notes each one contains.
On this page
A chord symbol gives the root, the quality, any extra notes and, after a slash, the bass note. C is a C major triad (C, E, G). Cm is a C minor triad (C, Eb, G). C7 adds a minor seventh (Bb), and Cmaj7 adds a major seventh (B). Each symbol is a short instruction about which notes to play and which of them goes lowest.
The root comes first, and the quality follows
The letter names the root, the note the chord is built on, whatever its inversion. The quality comes next. A plain letter means major, so C is C major. Minor is marked with a lowercase m, or occasionally a minus sign, so Cm is C minor. The rest of the symbol adds seventh notes, extensions, alterations and the bass, in roughly that order.
| Part of the symbol | Examples | What it adds |
|---|---|---|
| Quality | C, Cm, Cdim, Caug | The third and fifth of the triad |
| Seventh | C7, Cmaj7, Cm7 | A seventh above the root |
| Extension | C9, C11, C13 | Notes above the octave, with the seventh implied |
| Alteration | C7b9, C7#9, C7#5 | A chord tone moved by a semitone |
| Add | Cadd9, C6 | A note with no seventh |
| Suspension | Csus2, Csus4 | The third replaced by the second or fourth |
| Bass | C/E, C/G | A bass note other than the root |
Read the parts from left to right. C7b9 is still a dominant seventh with a flattened ninth: the b9 changes one note and leaves the seventh in place.
The seventh decides how the chord sounds
A seventh is the note seven scale steps above the root. In C, a minor seventh is Bb, ten semitones above C, and a major seventh is B, eleven semitones above C. The two differ by one semitone, and that single note changes the character of the chord.
The 7 in C7 means the minor seventh, which is why a dominant chord sounds unsettled. Writing maj7 raises the seventh by a semitone to B, and the chord sounds brighter and more settled. Compare the two:
The sequence is C major, then C7 with its Bb, then Cmaj7 with its B. The seventh is the only note that changes between the second and third chords, and that one note moves the sound from a chord that wants to resolve to one that rests.
Cm7 keeps the minor seventh of C7 but lowers the third. Its notes are C, Eb, G and Bb, which is the usual form of a minor seventh chord such as Dm7 or Am7 in a major key.
Minor, diminished and augmented chords change the third or the fifth
The three triad qualities differ only in their third and fifth. Cm lowers the third to Eb. Cdim lowers the third and the fifth: C, Eb and Gb. Caug raises the fifth: C, E and G#. Each chord has its own symbol, and all three are common in printed music.
Half-diminished chords need a separate symbol. Cm7b5 is C, Eb, Gb and Bb, a diminished triad with a minor seventh, and some lead sheets write it as Cø7. The fully diminished seventh, Cdim7, adds a note that is a diminished seventh above C. That note is written Bbb, a double flat, and it sounds as A. The chord is C, Eb, Gb and A, a stack of three minor thirds, which is why it divides the octave into equal parts. Double flats are awkward to read, which is why the spelling is seldom printed.
Add, six and nine chords are not seventh chords
A chord with a sixth instead of a seventh is written with a 6. C6 is C, E, G and A. It contains no seventh, so the sound is closer to a major triad with a bright added note than to a dominant chord.
The same four notes can be named two ways. A minor seventh chord on A is Am7, with the notes A, C, E and G. The notes are the same as C6, which is C, E, G and A, but the root is different. The chord’s name depends on which note the arranger wants the listener to hear as the root, and the bass usually decides it.
Cadd9 adds the ninth, D, to a plain triad: C, D, E and G. Because it has no seventh, the chord keeps the stable sound of the triad, with a faint added colour. C9 is different. It includes the minor seventh, Bb, and the ninth, D, so it is C, E, G, Bb and D. Writing 9 without “add” normally implies the seventh, and writing add9 normally means the seventh is absent.
Slash chords put a different note in the bass
After a slash, the symbol names the bass note. C/E is a C major triad with E as the lowest sound. The notes are the same as C major, but the bass changes the chord’s inversion and its sound: the E at the bottom sounds less settled than the root.
The first chord is C in root position, and the second is C/E, the first inversion of C major. The chord keeps its harmonic meaning, but the lowest line now sounds differently. One reason lead sheets use slash chords is to tell the bass player or the pianist’s left hand which note to sound.
A slash does not require the bass to be part of the chord. C/D puts D under a C major triad, so the lowest note is the ninth of the chord and the sound is close to Cadd9 with the ninth at the bottom. A run such as C, C/B, Am and C/G, where the bass steps down, is a common lead-sheet pattern, and only the slashes show that movement in the symbols.
Extensions and alterations: C7b9, Cm9 and C13
Extensions are chord tones above the octave. A ninth is the second, an eleventh is the fourth and a thirteenth is the sixth, all an octave higher. When a number is written, the seventh is implied below it: C9 includes Bb, C11 includes Bb and F, and C13 includes Bb, D, F and A. Writers often leave out the eleventh in a thirteenth chord because the fourth clashes with the third.
| Symbol | Notes on C | Meaning |
|---|---|---|
| Cm9 | C Eb G Bb D | minor seventh and ninth |
| C13 | C E G Bb D F A | dominant with the 13th, 11th often left out |
| C13 (11 omitted) | C E G Bb D A | the usual voicing |
| C7b9 | C E G Bb Db | dominant with a flattened ninth |
| C7#9 | C E G Bb D# | dominant with a sharped ninth |
The alteration b9 lowers the ninth by a semitone, from D to Db. It is one of the alterations that make a dominant chord sound tense, and it is written after the number to show that the ninth has been changed.
Those five notes are a dominant seventh with the flattened ninth above the octave. Db4 is a minor ninth above the bass C3, and that dissonance with the root gives the chord its tension. C7 is the dominant of F, so the chord pulls toward F major, and the flattened ninth makes the pull stronger.
Where this misleads people
The symbols are conventions, not a standard. Major is marked by its absence, minor by a lowercase m or a minus sign, and major sevenths by maj7, M7, Δ or a similar sign. Read the other symbols on the page and check the style before deciding what a symbol means. The capital M in CM7 and the lowercase m in Cm7 are easy to confuse at speed.
A symbol also describes a chord, not a voicing. Cm9 says which notes are present, but a pianist might play only the third, seventh and ninth, and a guitarist might leave out the root. The symbol does not decide the register, and it does not say which note is in the bass unless there is a slash.
Finally, the seventh is easy to misread. C7 has a minor seventh and Cmaj7 has a major one. The two differ by one semitone, and that semitone is the difference between a dominant and a tonic sound.
What to do with it
Choose a lead sheet with at least eight chord symbols. Before playing, write each chord’s notes from the table above, spelling them from the root. Then play the chord and check the notes with your ear. Keep a short list of the symbols that gave you trouble, and read it before the next session.
For the slash chords, play the bass line alone on the virtual piano, using only the bass note of each symbol. The line is what the listener follows first, so a wrong bass shows up immediately. The triads and inversions article explains the positions behind the slash, and seventh chords and resolution covers the tendencies of Cmaj7 and C7 in more detail.
Questions
What does Cmaj7 mean?
Cmaj7 is a C major seventh chord. It has the notes C, E, G and B: a C major triad with a major seventh, which is B, one semitone below the octave above C.
What is the difference between Cm7 and C7?
Cm7 has a minor third, Eb, and a minor seventh, Bb, so it is C Eb G Bb. C7 has a major third, E, and the same minor seventh, so it is C E G Bb. The third changes the quality from minor to major.
What does the slash in a chord symbol mean?
The note after the slash is the lowest sounding note. C/E is a C major chord with E in the bass, which is the first inversion of C major. The bass note can be a chord tone or a note from outside the chord.
What is the difference between C9 and Cadd9?
C9 is a seventh chord with a ninth added, so it contains a minor seventh, Bb, as well as D. Cadd9 is a plain C major triad with D added, and it has no seventh.
