A chord is a pattern of notes played simultaneously. There are many recognized patterns: these are given the familiar chord names based on the “root” note. For example, Am is a minor chord based on A. The table below shows the most common chords with an example based on A. The “Construction” column shows notes from the scale, where 1 is the root note (semitone 0 in the tables on the music theory page), 3 is the third, m3 is the minor third, #5 is the augmented fifth, b7 is the dominant seventh etc. These are not semitone gaps as in the music theory tables.
| Name | Notation (on A) | Construction | Notes (on A) |
|---|---|---|---|
| Major | A | 1-3-5 | A-C#-E |
| Minor | Am | 1-m3-5 | A-C-E |
| Seventh | A7 | 1-3-5-b7 | A-C#-E-G |
| Major seventh | Amaj7 or AΔ7 | 1-3-5-7 | A-C#-E-G# |
| Minor seventh | Am7 | 1-m3-5-b7 | A-C-E-G |
| Suspended "second" | Asus2 | 1-2-5 | A-B-E |
| Suspended fourth | Asus4 | 1-4-5 | A-D-E |
| Sixth | A6 | 1-3-5-6 | A-C#-E-F# |
| Minor sixth | Am6 | 1-m3-5-6 | A-C-E-F# |
| Ninth | A9 | 1-3-5-b7-9 | A-C#-E-G-B |
| Sixth/ninth | A6/9 | 1-3-5-6-9 | A-C#-E-F#-B |
| Major ninth | Amaj9 or AΔ9 | 1-3-5-7-9 | A-C#-E-G#-B |
| Minor ninth | Am9 | 1-m3-5-b7-9 | A-C-E-G-B |
| Added ninth | Aadd9 | 1-3-5-9 | A-C#-E-B |
| Eleventh | A11 | 1-3-5-b7-9-11 | A-C#-E-G-B-D |
| Minor eleventh | Am11 | 1-m3-5-b7-9-11 | A-C-E-G-B-D |
| Thirteenth | A13 | 1-3-5-b7-9-11-13 | A-C#-E-G-B-D-F# |
| Half-diminished | A°7 or Am7b5 | 1-m3-b5-b7 | A-C#-Eb-G |
| Diminished | Adim | 1-m3-b5-bb7 | A-C#-Eb-Gb |
| Augmented | A+ or Aaug | 1-3-#5 | A-C#-E# |
This is a big table, but it’s quite logical and there are a lot of patterns (G7 is G plus dominant seventh; G9 is G7 plus ninth (octave-and-tone); G11 is G9 plus eleventh (octave-and-fourth); G13 is G11 plus thirteenth (octave-and-sixth)).
Self-test question 1
What notes are in the chord of C major?
C-E-G. The root is C, and you need the third and fifth, which are E and G. .
Interval: root third fifth Semitone interval: 0 4 7 Note: C E G
Self-test question 2
What notes are in the chord of F#m7?
F#-A-C#-E. The minor seventh chord contains root, minor third, fifth and dominant (flattened) seventh (1-m3-5-b7).
Interval: root minor third fifth dominant seventh Semitone interval: 0 3 7 10 Note: F# A C# E
Self-test question 3
What is E-G#-B-D#-F#?
Emaj9. If you need to go back to semitone gaps, these are: 0-4-7-11-14, which are the root, major third, fifth, major seventh, and ninth. If you don’t recognize that as a maj9 chord, rewrite it as 1-3-5-7-9 and refer to the table above.
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