Learning chords and chord progressions can feel like simple memorization for beginners just starting on the guitar. But more complex chords can be hard to learn without a deeper understanding of the theory and structure behind them. This article covers guitar chord theory, including the basics of intervals and how chords are formed to help you take your playing to the next level.
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Basics of Intervals
Guitar chords get their structures, and often their names, from the intervals they’re built on. A true understanding of guitar chord theory demands a thorough knowledge of intervals and how they work. Once you’ve mastered the theory of intervals, guitar chords will make much more sense.
Intervals describe the distance between two separate pitches. They’re measured in steps, as in from C to D, and half-steps, as in from C to D flat. Intervals are universal across instruments and genres.
If the notes in an interval are played in sequence, one after the other like in a guitar riff, it’s called a melodic interval. If they’re played simultaneously, like in a guitar chord, it’s called a harmonic interval. Each interval has a name that describes it.
- Perfect Unison (P1).
The unison interval is made up of two of the same note, as in the opening notes of The Imperial March (Darth Vader’s Theme) by John Williams. - Minor Second (m2).
This interval is the gap between notes one-half step – one fret – apart. The minor second sounds like the iconic “Jaws” theme when played sequentially. - Major Second (M2).
The major second interval is the space between notes one whole step – two frets – apart. When played sequentially, this interval sounds like the opening notes of “Happy Birthday.” - Minor Third (m3).
The minor third is made of notes with a distance of one and a half steps – three frets – between them. This interval sounds like the melody of “Brahm’s Lullaby“ when played sequentially. - Major Third (M3).
This interval is the gap between notes two whole steps – or four frets – apart. When played sequentially, it sounds like the third and fourth notes in “Beethoven’s 5th Symphony“. - Perfect Fourth (P4).
The notes in a perfect fourth are two and a half steps – five frets – apart. The opening two notes of “Amazing Grace” are a perfect fourth interval. - Tritone (TT), Augmented Fourth (A4), and Diminished Fifth (D5).
This interval has three different names depending on the context. Its notes are three whole steps – six frets – apart, and it sounds like the first two notes of “The Simpsons” theme. - Perfect Fifth (P5).
The notes in a perfect fifth interval are three and a half steps – seven frets – apart. It sounds like the opening of “Twinkle Twinkle, Little Star.” - Minor Sixth (m6).
The minor sixth interval’s notes are four whole steps – eight frets – apart. The iconic melody in the ragtime piano tune “The Entertainer” uses this interval. - Major Sixth (M6).
Notes in a major sixth interval are four and a half steps – nine frets – apart. The first two notes in the “NBC Chimes” form a major sixth interval. - Minor Seventh (m7).
The minor seventh interval contains notes five whole steps – ten frets – apart. The soaring sequence in the original Star Wars theme is a minor seventh interval. - Major Seventh (M7).
The major seventh interval is just shy of an octave, at five and a half steps – eleven frets – apart. The best-known example of this interval is in the chorus of the song “Take On Me” by Aha. - Octave (P8).
This interval comprises two notes with the same name at a higher register, six whole steps – twelve frets – apart. The first two notes in the phrase “Somewhere Over the Rainbow” are an octave interval.
Types of Chords
Each guitar chord is built on one or more harmonic intervals played simultaneously. The base note of the chord, called the root, gives the chord its name. The intervals above the root note tell you how to play the full chord.
Guitar chords fall into three main categories – triads, sevenths, and extended chords.
Power Chords
Power chords are abbreviated chords that contain only two notes – usually the root note and the perfect fifth. For example, the C power chord uses C and G, but you leave out E or Eb.
These chords can be easy to learn since you have fewer notes to remember. They only require one or two fingers as well. You can even add an octave (P8) to the chord to make it sounds more powerful.
Triads
Triads are chords built on three notes played simultaneously. On guitar, the notes in a triad may be “doubled” on multiple strings for a fuller sound. Most of the basic chords guitar players learn as beginners are triads.
Each triad has two intervals – between the root note and the second note, and between the root note and the third note. Different intervals between notes in a triad produce different types of chords. To learn more about Triads, please check out our guide Triads and Inversions(coming soon).
Major Triads
A major triad is the most basic form of a major chord. From the root of a major triad, the second note is a major third(M3), and the third note is a perfect fifth(P5). For example, the root of a C major triad is C, and the complete triad is C, E, G.
Major triads are among the most common guitar chords, especially for beginners. Songs made up primarily of major chords tend to sound upbeat. The shorthand for a major triad is the root note’s name. For example, the shorthand for a C chord is simply “C.”
Minor Triads
A minor triad is similar in structure to a major triad, with the first interval flattened. From the root of a minor triad, the second note is a minor third(m3), and the third note is a perfect fifth(P5). For example, an A minor triad is made of the notes A, C, and E.
Minor triads tend to sound dark and brooding. The shorthand for a minor triad is the letter of the root note followed by a lowercase letter m. For example, “Am” is shorthand for an A minor chord.
Suspended Chords
The construction of a suspended triad begins with a major triad, raising or dropping the interval of the major or the minor third note. From the root of a suspended triad, the second note is a perfect fourth(P4) or a major second(M2), and the third note is a perfect fifth. For example, a C suspended fourth chord is made of the notes C, F, and G. And a C suspended second chord is made of the notes C, D and G.
Suspended chords add a sense of tension to the music, which often goes unresolved. The shorthand for a suspended chord is the root note’s letter followed by the abbreviations “sus4” and “sus2”. For example, a C suspended chord is often written “C sus4” or “C sus2”.
Augmented Chords
The structure of an augmented chord is based on the major triad, but the second interval is extended a half-step. From the root of an augmented triad, the second note is a major third, and the third note is an augmented fifth (also known as a minor sixth). For example, the notes in a C augmented chord are C, E, and G♯.
Augmented chords are suspenseful and dissonant. Jazz and blues music tends to use a lot of augmented chords. The shorthand for an augmented chord is the letter of the root note followed by the abbreviation “aug” or “+”. For example, the shorthand for a C augmented chord is “C aug” or “C+”.
Diminished Chords
Diminished chords are based on the major triad, with the second and third notes flattened. From the root note of a diminished triad, the second note is a minor third, and the third note is a diminished fifth (also known as an augmented fourth, or tritone). For example, the notes in a C diminished chord are C, E♭, and G♭.
Diminished chords build tension, like a melancholy minor chord with the dissonance dialed up. The shorthand for a diminished chord is the letter of the root note followed by the abbreviation “dim” or “o” For example, the shorthand for a C diminished chord is “C dim” or “Co.”
Seventh Chords
Unlike triads, which have three notes, seventh chords have four. As the name suggests, the fourth note is based on a seventh interval from the root note. Because they have four notes, they have three separate intervals. As with triads, varying the intervals of a seventh chord changes the sound of the chord and chord type.
Major 7th Chords
The simplest form of the seventh chord is a major seventh, which is a major triad with a fourth note at the seventh interval. From the root of a major seventh chord, the second note is a major third, the third note is a perfect fifth, and the fourth note is a major seventh. For example, the notes in a C major seventh are C, E, G, and B.
Major sevenths are common in jazz music. The shorthand for a major seventh chord is the root note, followed by the abbreviation “maj7”. For example, a C major seventh is abbreviated as Cmaj7.
Dominant 7th Chords
As the name suggests, the dominant seventh chord is the most commonly used seventh chord. Its construction is the same as a major seventh, with the fourth note flattened. From the root of a dominant seventh, the second note is a major third, the third note is a perfect fifth, and the fourth note is a minor seventh. For example, the notes in a C dominant seventh are C, E, G, and B♭.
Dominant sevenths are common in all genres of music. The shorthand for a dominant seventh chord is the root note followed by the number 7. For example, a C dominant seventh is abbreviated simply as C7.
Minor 7th Chords
Minor seventh chords have the same structure as a dominant seventh, with the second note flattened. From the root note of a minor seventh, the second note is a minor third, the third note is a perfect fifth, and the fourth note is a minor seventh. For example, the notes in a C minor seventh are C, E♭, G, and B♭.
The shorthand for a minor seventh chord is the root note followed by the abbreviation “m7.” For example, a C minor seventh is notated as “Cm7.”
Augmented 7th Chords
Augmented seventh chords are based on the structure of augmented triads, with the addition of the flattened seventh found in dominant seventh chords. From the root of an augmented seventh chord, the second note is a major third, the third is an augmented fifth (also known as a minor sixth), and the fourth is a minor seventh. For example, the notes in a C augmented seventh are C, E, G♯, and B♭.
The shorthand for an augmented seventh chord is the root note followed by “aug7,” as in “Caug7.”
Diminished 7th Chords
Diminished seventh chords are based on diminished triads, with the addition of a diminished seventh interval. From the root of a diminished seventh chord, the second note is a minor third, the third note is a diminished fifth, and the fourth note is a diminished seventh. For example, the notes in a C diminished seventh are C, E♭, G♭, and B♭♭.
Yes, you read that correctly – B flat flat, which is also A. But because the diminished seventh is a variation of the dominant seventh structure, most musicians find it more intuitive to read when written this way. The shorthand for a diminished seventh chord is “dim7” or “o7”, as in “Cdim7” or “Co7”.
Extended Chords
Major 7th add 9th/11th/13th
Minor 7th add 9th/11th/13th
Dominant 9th/11th/13th
Extended chords are chords built on more than four notes, extending beyond the seventh interval. Extended chords have a wide range of variations, encompassing all the triad and seventh chord structures, with the addition of ninths, elevenths, and thirteenths as well.
The notation of extended chords describes the notes contained within them. For example, a C9 chord has a root of C and extends to the 9th interval. That means it contains the notes C, E, and G (from C major), B♭ (from C dominant seventh), and D (the ninth). Likewise, a Cm11 contains the notes C, E♭, G, and B♭ (from C minor seventh), D (the ninth), and F (the eleventh).
Added Tone Chords / Add Chords
The structure of an added tone chord is based on the major triad but with the addition of any note but not a seventh. It can be a sixth, ninth, eleventh, or even thirteenth interval. An eighth interval is actually an octave of the roof so a ninth interval will be a second interval but octaved, an eleventh is an octaved fourth, etc. From the root of a major triad, the second note is a major third(M3), and the third note is a perfect fifth(P5), then the fourth note can be a ninth or an eleventh. For example, the root of a C major triad is C, and the complete triad is C, E, G and D.
An added chord is most likely to substitute a normally traditional chord to add an extra voice to the chord. The shorthand for an added chord is the letter of the root note followed by the abbreviation “add9”, “add11” and “add13”. For example, a Cadd9 chord has a C Major chord and adds the 9th interval. That means it contains the notes C, E, and G (from C major), and D (the ninth). Likewise, a Cadd11 contains the notes C, E, G, and D (the ninth), and F (the eleventh).
Besides the added chords, there are two added chords that aren’t like the others. They are “6” and “6add9”.
Since there is an add13 chord which is an octave of a sixth interval, A 6 chord is obviously a minor or a major chord and adds a sixth interval to it. A 6add9 chord will have to add another interval which is a ninth. The shorthand for them is the root note’s letter followed by the abbreviations “6” and “6add9”; “m6” and “m6add9” for the minor: for example C6 and C6add9 for the major; Cm6 and Cm6add9 for the minor.
Some of the added or extended chords sometimes are very hard to play, so the 5th is typically omitted on those chords.
What To Do Next?
Memorizing simple chord progressions as a beginner is a great way to get started playing guitar. But by understanding the theory behind chords and how they’re formed, you open up a whole new world of complex and intricate chord patterns. When you know the intervals and formulas behind different types of chords, you can play just about anything on the guitar. Please check our article 10 Easy Guitar Songs for Beginners to practice the common chords and go master those chords!
