Chord Structure

Chords, Symbols, Formulas...

Chord structure consists of notes and intervals which can vary from 2-note chords and their respective intervals right up to 7-note chords and everything in between.

We will concentrate on the structure of 3-note chords for this session followed by a comprehensive chart detailing a variety of popular chords by name, type, symbol and formula.

Triads: 3-note chords

A triad is a 3-note chord stacked vertically in thirds. From lowest to highest pitch the chord consists of:

  • root - chord foundation
  • third - minor third (3 semi-tones) or major third (4 semitones)
  • fifth - minor or major third above the third interval. The interval above the root can be a diminished fifth (6 semitones), a perfect fifth (7 semitones), or an augmented fifth (8 semitones) - with the perfect fifth most commonly used in popular western music.
  • Please note that in triads, the root note doesn't have to be the lowest note in the chord due to the principle of inversion, but it will always remain the root note.

While the root note determines the chord's function and the interval from one note to the next is a third, the quality of the third is determined by the quality of the triad:

  • major triad infers the 3rd and 5th are untouched
  • minor triad infers the 3rd is flattened
  • diminished triad infers the 3rd and 5th are flattened
  • augmented triad infers the 5th is sharpened
Triad Intervals Formula Semitones
Major Major 3rd, Perfect 5th 1 - 3 - 5 0 - 4 - 7
Minor Minor 3rd, Perfect 5th 1 - b3 - 5 0 - 3 - 7
Diminished Minor 3rd, Dim 5th 1 - b3- b5 0 - 3 - 6
Augmented Major 3rd, Aug 5th 1 - 3 - #5 0 - 4 - 8

If we were stacking thirds:

Triad Thirds Example Semitones
Major Major 3rd + Minor 3rd C C - E - G
Minor Minor 3rd + Major 3rd Cm C - Eb - G
Diminished Minor 3rd + Minor 3rd Cdim C - Eb - Gb
Augmented Major 3rd + Major 3rd Caug C - E - G#

You will find a more detailed explanation about these intervals and stacking thirds including 4, 5 and 6-note chords along with relevant charts on the music chords page.

Chords - Types - Symbols - Formulas

There are many symbols associated with chord types, and each one describes the type of chord and what notes will be played in the chord.

The following chart shows you the chords, symbols and formulas for almost every chord you will ever play. If you know your scales and chord formulas you will be able to calculate the notes of any chord for any instrument that utilizes chords. With the major chords, the symbol ? indicates the chord in question, therefore a C major chord can quite simply be written as C... any chord written without other references or symbols is always a major chord.

Chords Chord Type Chord Symbols Formula (notes)
Triads: Major ?,  M,  Δ,  ma, maj 1 - 3 - 5
3 note chords Minor m,  - ,  mi,  min 1 - ♭3 - 5
  Diminished dim,  º ,  m(♭5) 1 - ♭3 - ♭5
  Diminished 5th  -5 1 - 3 - ♭5
  Augmented aug, +  1 - 3 - #5
  Suspended 4th sus, sus4 1 - 4 - 5
  Suspended 2nd sus2 1 - 2 - 5
 
7th Chords: Dominant 7th 7, dom7 1 - 3 - 5 - ♭7
4 note chords Minor 7th m7, min7, -7 1 - ♭3 - 5 - ♭7
  Major 7th maj7,  M7,  ∆7 1 - 3 - 5 - 7
  Minor Major 7th  mM7, minMaj7 1 - ♭3 - 5 - 7  
  Suspended 7th 7sus4 1 - 4 - 5 - ♭7
  Augmented 7th  +7,  aug7,  7+5,  7#5 1 - 3 - #5 - ♭7
  Augmented Major 7th +M7,  M7+5,  M7#5 1 - 3 - #5 - 7
  7th Augmented Ninth  7+9 1 - 3 - 5 - ♭7 - # 9
  Half Diminished 7th ø7,  m7b5,  m7-5, -7(b5) 1 - ♭3 - ♭5 - ♭7
  Diminished 7th о7,  dim 7 1 - ♭3 - ♭5 - ♭♭7
  7th Diminished Fifth 7 -5 1 - 3 - ♭5 - ♭7
  7th Flat Nine 7 -9 1 - 3 - 5 - ♭7 - ♭9
 
6th Chords: Sixth 6 1 - 3 - 5 - 6
4 note chords Minor 6 m6 1 - ♭3 - 5 - 6
5 note chords Major 6th with added 9th 6/9 1 - 3 - 5 - 6 - 9
 
9th Chords Ninth 9 1 - 3 - 5 - ♭7 - 9
5 note chords Minor Ninth  m9 1 - ♭3 - 5 - ♭7 - 9
  Major Ninth  maj9,  M9,  ∆9 1 - 3 - 5 - 7 - 9
  Ninth Diminished Fifth  9 -5 1 - 3 - ♭5 - ♭7 - 9
 
11th Chords: 6 note Eleventh 11 1 - 3 - 5 - ♭7 - 9 - 11
       
13th Chords: 7 note Thirteenth (11th usually omitted) 13 1 - 3 - 5 - ♭7 - 9 - 11 - 13


Chord Structure

I hope you have enjoyed this session on Chord Structure. Next time you are playing and are unsure of how to play certain chords, knowing the formulas can be a great asset. You might be thinking, how can I remember all these formulas? The more you play and take note of chord formulas, the more you will remember them. This is especially useful when playing guitar and you need that chord high up the neck towards the guitar body. As long as you know your scales, formulas, and guitar notes, you can make up any chord - anywhere... very handy.

Back to Music Chords Theory

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