Chords are the vertical building blocks of music. While melodies move horizontally through time, chords stack notes on top of each other to create harmony. If you understand how chords are built, you can construct any chord in any key without relying on memorization or chord charts. The underlying principle is elegant: nearly every chord is built by stacking intervals of a third.
What intervals do you need to know to build chords?
You need exactly two intervals: the major 3rd (four half steps, like C to E) and the minor 3rd (three half steps, like C to Eb). With those two intervals and the order in which you stack them, you can construct every standard triad and seventh chord in Western music.
Before building chords, you need two intervals in your toolkit:
- Major third (M3): four half steps. Example: C to E.
- Minor third (m3): three half steps. Example: C to E-flat.
That is it. With just these two intervals, you can build every standard triad and seventh chord.
What are the four types of triads and how are they built?
A triad is a three-note chord built by stacking two thirds. Major triad: M3 + m3 (C-E-G, bright). Minor triad: m3 + M3 (C-Eb-G, dark). Diminished triad: m3 + m3 (C-Eb-Gb, tense). Augmented triad: M3 + M3 (C-E-G#, shimmering). The stacking order determines the quality.
Major Triad (M3 + m3)
Start with the root, add a major third, then add a minor third on top of that.
C major triad: C - E - G
- C to E: major third (4 half steps)
- E to G: minor third (3 half steps)
- Total span from C to G: perfect fifth (7 half steps)
The major triad sounds stable, bright, and resolved. It is the most common chord type in Western music.
Minor Triad (m3 + M3)
Reverse the order: start with a minor third, then a major third.
C minor triad: C - E-flat - G
- C to E-flat: minor third (3 half steps)
- E-flat to G: major third (4 half steps)
- Total span: still a perfect fifth
The minor triad sounds darker and more introspective than its major counterpart, but it is equally stable. Notice that the only difference between C major and C minor is the third: E vs. E-flat.
Diminished Triad (m3 + m3)
Stack two minor thirds.
C diminished triad: C - E-flat - G-flat
- C to E-flat: minor third
- E-flat to G-flat: minor third
- Total span: diminished fifth, also called a tritone (6 half steps)
The diminished triad sounds tense and unstable, like it urgently needs to resolve somewhere. In a major key, it naturally occurs on the seventh scale degree (B diminished in C major: B - D - F).
Augmented Triad (M3 + M3)
Stack two major thirds.
C augmented triad: C - E - G-sharp
- C to E: major third
- E to G-sharp: major third
- Total span: augmented fifth (8 half steps)
The augmented triad has a shimmering, unresolved quality. It appears less frequently than major and minor triads but is a favorite in jazz, film scores, and Beatles songs (“Oh! Darling” uses augmented chords prominently).
What is a quick reference for triad construction?
| Chord Type | Formula | Example (root = C) | Sound |
|---|---|---|---|
| Major | M3 + m3 | C - E - G | Bright |
| Minor | m3 + M3 | C - Eb - G | Dark |
| Diminished | m3 + m3 | C - Eb - Gb | Tense |
| Augmented | M3 + M3 | C - E - G# | Shimmering |
What is a seventh chord and how is it built?
A seventh chord is a triad with one more third stacked on top, creating a four-note chord that includes the 7th degree above the root. There are five common types: major 7th, dominant 7th, minor 7th, half-diminished 7th, and diminished 7th. They are the foundation of jazz and modern pop harmony.
Seventh chords extend a triad by stacking one more third on top, adding a fourth note. This creates richer, more colorful harmony. There are five common seventh chord types.
Major 7th (Maj7)
Take a major triad and add a major third on top.
Cmaj7: C - E - G - B
The interval from the root to the seventh is a major seventh (11 half steps). Major 7th chords sound lush, warm, and sophisticated. They are a staple of jazz, bossa nova, and R&B. Think of the opening chord of Stevie Wonder’s “You Are the Sunshine of My Life.”
Dominant 7th (7)
Take a major triad and add a minor third on top.
C7: C - E - G - B-flat
The interval from root to seventh is a minor seventh (10 half steps). Despite using a major triad as its base, the dominant 7th chord contains a tritone between its third and seventh (E to B-flat), which creates tension that wants to resolve. In classical harmony, the dominant 7th chord (built on scale degree V) resolves to the tonic. G7 resolves to C major. This V-I resolution is the most fundamental harmonic motion in tonal music.
Minor 7th (m7)
Take a minor triad and add a minor third on top.
Cm7: C - E-flat - G - B-flat
Both the third and seventh are minor intervals from the root. Minor 7th chords sound mellow and open. They dominate jazz, neo-soul, and lo-fi hip hop.
Half-Diminished 7th (m7b5)
Take a diminished triad and add a major third on top.
Cm7b5 (also written C half-diminished): C - E-flat - G-flat - B-flat
This chord appears naturally on the seventh degree of a major key (Bm7b5 in C major) and on the second degree of a minor key (Dm7b5 in C minor). It functions as a pre-dominant chord in minor-key ii-V-i progressions, which are everywhere in jazz.
Diminished 7th (dim7)
Take a diminished triad and add a minor third on top.
Cdim7: C - E-flat - G-flat - B-double-flat (enharmonically A)
Every note in a diminished 7th chord is separated by a minor third, dividing the octave into four equal parts. This symmetry means there are really only three distinct diminished 7th chords — all the rest are inversions. The sound is dramatic and suspenseful, frequently used in classical music, film scores, and as a passing chord in jazz.
What is the chord formula approach using scale degrees?
Instead of stacking thirds, you can think in scale degrees relative to the major scale: major = 1-3-5, minor = 1-b3-5, dominant 7th = 1-3-5-b7, and so on. If you know the major scale for any root, you can build any chord type instantly by applying the formula.
- Major: 1 - 3 - 5
- Minor: 1 - b3 - 5
- Diminished: 1 - b3 - b5
- Augmented: 1 - 3 - #5
- Maj7: 1 - 3 - 5 - 7
- Dom7: 1 - 3 - 5 - b7
- Min7: 1 - b3 - 5 - b7
- Half-dim7: 1 - b3 - b5 - b7
- Dim7: 1 - b3 - b5 - bb7
The “1” is the root, “3” is the major third of the scale, “b3” is the minor third, and so on. If you know your major scale for any root note, you can apply these formulas instantly.
How do you build a chord in any key — a worked example?
To build F#7: start with the F# major scale (F#-G#-A#-B-C#-D#-E#-F#), apply the dominant 7th formula 1-3-5-b7, and read off the notes: F#, A#, C#, E. The same process works for any chord type in any key as long as you know the major scale for the root.
Let us build an F-sharp dominant 7th chord (F#7) from scratch.
- Start with the F-sharp major scale: F# - G# - A# - B - C# - D# - E# - F#
- Apply the dominant 7th formula: 1 - 3 - 5 - b7
- Pick out the notes:
- 1 = F#
- 3 = A# (the third degree of F# major)
- 5 = C# (the fifth degree)
- b7 = E (lower the seventh degree E# by a half step)
F#7 = F# - A# - C# - E
The process works for any chord type in any key. Know the major scale, apply the formula, done.
What is a chord inversion?
A chord inversion is the same chord with a different chord tone in the bass. Root position has the root on the bottom; first inversion has the 3rd on the bottom; second inversion has the 5th on the bottom. Inversions do not change the chord’s name — they change which note is lowest, enabling smoother voice leading.
A chord does not always have its root as the lowest note. When a different chord tone is in the bass, the chord is inverted:
- Root position: root on the bottom (C - E - G)
- First inversion: third on the bottom (E - G - C)
- Second inversion: fifth on the bottom (G - C - E)
- Third inversion (7th chords only): seventh on the bottom (B-flat - C - E - G)
Inversions do not change the chord’s name or function, but they change its voice leading and how smoothly it connects to the next chord. Skilled arrangers use inversions to create smooth bass lines where the bass note moves by step rather than leaping.
What practice habits actually internalize chord construction?
Start in one key (C), build all four triads and five 7th chord types from that root, then move around the circle of fifths. Use a piano even if you play guitar (the visual layout helps). Spell each chord out loud as you play. Analyze chord types in songs you love.
Start with one key. Build all four triad types and all five seventh chord types from C. Then move to G, then D, following the circle of fifths. By the time you reach F-sharp, you will have covered every key.
Use a keyboard. Even if you are primarily a guitarist or singer, a piano keyboard makes chord construction visual. You can see the half steps and whole steps laid out physically.
Spell chords out loud. Say “D minor seven: D, F, A, C” before you play it. Engaging your verbal memory alongside your muscle memory accelerates learning.
Analyze songs you love. Take a chord progression from a favorite song and identify each chord’s type. Is that an Am7? A Gmaj7? A D7? Connecting theory to music you already care about makes the knowledge stick.
Build your chord vocabulary hands-on with Music Genius. The Build the Chords game gives you a target chord symbol and asks you to select the correct notes, helping you internalize chord formulas through active practice. Pair this guide with Seventh Chords Explained and Chord Inversions Guide to round out the topic.
Frequently Asked Questions
How do you build a chord from scratch?
Stack intervals of a third on top of a root note. A triad is three notes; a seventh chord is four. The pattern of major and minor thirds you stack determines the chord quality. Major triad = major 3rd then minor 3rd. Minor triad = minor 3rd then major 3rd. The same logic extends to every standard chord.
What is a triad in music?
A triad is a three-note chord built by stacking two thirds on top of a root note. There are four triad types: major (M3+m3), minor (m3+M3), diminished (m3+m3), and augmented (M3+M3). Triads are the foundation of nearly all Western harmony and the building blocks of more complex chords.
How is a major chord built?
A major chord (triad) is built by stacking a major 3rd then a minor 3rd above the root. From C: C + E + G. The formula in scale degrees is 1-3-5. The span from root to top note is a perfect 5th. Major chords sound bright, stable, and resolved — the most common chord type in Western music.
How is a minor chord built?
A minor chord (triad) is built by stacking a minor 3rd then a major 3rd above the root. From C: C + Eb + G. The formula is 1-b3-5. The only difference from a major chord is the lowered 3rd, which produces the darker, more introspective minor sound. The 5th remains the same perfect 5th.
What is a seventh chord?
A seventh chord is a four-note chord — a triad with one more third stacked on top, adding a 7th above the root. The five common types are major 7th (Cmaj7), dominant 7th (C7), minor 7th (Cm7), half-diminished 7th (Cm7b5), and diminished 7th (Cdim7). Each has a distinct color used heavily in jazz, R&B, and pop.
What is the difference between Cmaj7 and C7?
Cmaj7 is C + E + G + B — a major triad plus a major 7th. It sounds lush and resolved. C7 (dominant 7th) is C + E + G + Bb — a major triad plus a minor 7th. The lowered 7th creates a tritone between E and Bb, producing tension that wants to resolve to F or another tonic chord.
What is a chord inversion?
A chord inversion is the same chord with a different note in the bass. Root position has the root on the bottom (C-E-G). First inversion puts the 3rd on the bottom (E-G-C). Second inversion puts the 5th on the bottom (G-C-E). Inversions do not change the chord's name or function — they change voice leading.
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