How Guitar Chords Are Built: Triads, 7ths, and Beyond

Introduction to Chord Construction

Every chord you’ve ever played is built from a simple formula. Once you understand how chords are constructed, you’ll stop memorizing random finger positions and start understanding music from first principles. You’ll be able to build any chord, understand why certain chords work together, and create voicings that fit your musical needs.

Chord construction starts with intervals—the distances between notes. Stack the right intervals together, and you get a chord. This is true for simple triads and complex jazz chords with nine different notes.

Building Triads: The Foundation

A triad is the simplest chord: three notes stacked on top of each other. Let’s start with the C major scale: C-D-E-F-G-A-B. To build a chord, you take every other note. Start on C: C (first), E (third), G (fifth). That’s a C major triad.

The relationship between the notes matters more than the notes themselves. A major triad always contains a root, a major third (4 semitones above the root), and a perfect fifth (7 semitones above the root).

Major Triad Formula: Root + Major 3rd + Perfect 5th

For C major: C (root) + E (major 3rd, 4 semitones up) + G (perfect 5th, 7 semitones up).

Minor Triad Formula: Root + Minor 3rd + Perfect 5th

For C minor: C (root) + Eb (minor 3rd, 3 semitones up) + G (perfect 5th, 7 semitones up). The only difference is lowering the third by one semitone. This small change creates a dramatically different emotional quality.

On guitar, these triads can be played in many positions. A triad on the high three strings (like a D major triad on frets 10-10-11 on strings 4-3-2) is the same triad as the open D chord, just inverted. Same three notes, different arrangement.

Seventh Chords: Adding Complexity

A seventh chord adds one more note to the triad: a seventh degree note from the scale. This single addition creates four distinct types of seventh chords, each with its own flavor.

Major Seventh (Maj7): Root + Major 3rd + Perfect 5th + Major 7th. Example: Cmaj7 is C-E-G-B. The major seventh (B) is 11 semitones from C. This chord has a bright, sophisticated sound, common in jazz and sophisticated pop.

Minor Seventh (min7): Root + Minor 3rd + Perfect 5th + Minor 7th. Example: Cm7 is C-Eb-G-Bb. The minor seventh (Bb) is 10 semitones from C. This is the workhorse chord of blues, funk, and jazz.

Dominant Seventh (dom7 or 7): Root + Major 3rd + Perfect 5th + Minor 7th. Example: C7 is C-E-G-Bb. It combines a major third with a minor seventh, creating tension that wants to resolve. Blues music is built on dominant seventh chords.

Minor Major Seventh (min/maj7): Root + Minor 3rd + Perfect 5th + Major 7th. Example: Cm(maj7) is C-Eb-G-B. This unusual combination is less common but appears in advanced jazz and film music.

Extended Chords: Ninths, Elevenths, and Thirteenths

Once you understand sevenths, extended chords are just continuations. You keep stacking thirds above the seventh.

A ninth chord adds the 9th scale degree (2 semitones above the octave). Cmaj9 is C-E-G-B-D. A dominant 9th (C9) is C-E-G-Bb-D. These chords have an open, spacious sound.

An eleventh chord adds the 11th degree. An 11th is unusual on major and dominant chords (it conflicts with the major 3rd) but natural on minor chords. Cm11 is C-Eb-G-Bb-F.

A thirteenth chord adds the 13th degree (or 6th). These are the most colorful chords. Cmaj13 is C-E-G-B-D-A. On guitar, these extended chords are typically voiced with the 3rd, 7th, and top notes, leaving out the low extensions.

Sus Chords and Add Chords

Sus (suspended) and add chords modify the basic triad differently. Instead of stacking thirds, you’re replacing or adding specific intervals.

Suspended Second (sus2): Root + Major 2nd + Perfect 5th. Csus2 is C-D-G. You’ve replaced the major third with a second. It’s open and ambiguous, used to create tension before resolving to a major chord.

Suspended Fourth (sus4): Root + Perfect 4th + Perfect 5th. Csus4 is C-F-G. This is more common than sus2. It’s that classic open, ringing sound you hear in many rock songs. It resolves beautifully to major or minor chords.

Add9 and Add Chords: Instead of replacing the third, you add an extension on top. Cadd9 is C-E-G-D (the triad plus the ninth). This is different from Csus2 because you keep the major third. These chords have a rich, colorful sound without the tension of sevenths.

Power Chords: The Minimalist Approach

Power chords (often called 5 chords) are the simplest chords: just the root and the fifth. C5 is C-G. There’s no third, so technically it’s neither major nor minor—it’s neutral.

Power chords are essential for rock and metal. They’re easy to play, they cut through distortion, and they’re moveable up and down the neck instantly. Two strings, two or three fingers, and you can play power chords anywhere.

The power chord is also the foundation for understanding voicing. When you add the major or minor third back, the power chord becomes major or minor. When you add more notes (seventh, ninth, etc.), you’re building on that neutral power chord foundation.

Building Chords from Intervals

The most powerful approach to chord construction is thinking in intervals. Instead of memorizing shapes, you memorize interval relationships.

Every chord can be described as a collection of intervals above the root. A major triad is a major 3rd plus a perfect 5th. A dominant seventh is a major 3rd, perfect 5th, and minor 7th.

On guitar, intervals have consistent shapes. A major 3rd is always 4 semitones. If you can visualize interval shapes on your fretboard, you can build any chord anywhere. A major 3rd from the low E string at the 2nd fret (F#) is two frets up on the D string (A).

This approach scales perfectly. Learn the interval shapes, combine them, and you’ve got infinite chords at your fingertips.

Voicings and Inversions

The same three notes can be arranged in different orders. C-E-G (root position), E-G-C (first inversion), or G-C-E (second inversion) are all C major triads with different characters.

Root position (root on bottom) is solid and grounded. First inversion (third on bottom) is lighter and more elegant. Second inversion (fifth on bottom) is hollow and ambiguous.

On guitar, you’re constantly using inversions without thinking about it. An open C chord (X32010) is actually C-E-G-C-E in first inversion. Learning to recognize and intentionally use inversions gives you more control over the character and flow of your chord progressions.

Continue your learning journey with these related lessons:

FAQ

What’s the easiest way to learn chord construction?

Start with major and minor triads. Learn the formula (major = 1-3-5, minor = 1-b3-5), build them on different root notes, and hear the difference. Then add sevenths one at a time. Once triads and sevenths click, everything else follows the same logic.

Do I need to know all the extended chords?

For basic playing, major, minor, seventh, and sus4 chords cover most songs. Extended chords are valuable for jazz, funk, and sophisticated styles. Learn them as you need them, but don’t feel pressured to master all of them immediately.

How do voicings relate to chord theory?

Voicings are the practical application of chord theory. The theory tells you which notes make up a chord; voicings tell you where to play those notes on the guitar. Different voicings of the same chord have the same notes but different colors.

Can I create my own chords?

Absolutely. If you understand intervals, you can stack them however you like. Not every combination will sound musical, but experimentation is how you discover sounds. Try unusual chord combinations and see what resonates.