How Chords Are Built | Ukulelearn lessons

Chords aren't arbitrary shapes you memorize. They're intervals stacked in a specific pattern. Once you see that pattern, you can understand any chord name - and eventually build your own voicings instead of just copying diagrams.

The Major Triad: 1-3-5

Every basic chord starts with three notes called a triad. The major triad uses the 1st, 3rd, and 5th degrees of the major scale.

In C major: C (1), E (3), G (5). That's a C major chord.

The interval from the root to the 3rd is a major 3rd (4 half steps). From the 3rd to the 5th is a minor 3rd (3 half steps). Stack them and you get the characteristic bright, stable sound of a major chord.

The Minor Triad: 1-b3-5

Flatten the 3rd by one half step and the chord goes minor. The minor triad uses the 1st, flattened 3rd, and 5th.

In A minor: A (1), C (b3), E (5). That's an Am chord.

The interval structure flips: minor 3rd from root to b3 (3 half steps), then major 3rd from b3 to 5th (4 half steps). Major and minor are the same chord with one note changed by a single half step. That's why they're so closely related.

7th Chords: Adding the 4th Note

Add one more 3rd above the 5th and you get a 7th chord. The type of 7th changes the flavor:

Major 7th (maj7): 1-3-5-7. Smooth, sophisticated. Cmaj7 has a B on top.
Dominant 7th (7): 1-3-5-b7. Creates tension that resolves to the I chord. G7 wants to go home to C.
Minor 7th (m7): 1-b3-5-b7. Warm and relaxed. Am7 is softer than a plain Am.

Chord Symbols Decoded

Once you know the system, chord names tell you exactly what intervals are present:

C = 1-3-5 (major triad)
Cm = 1-b3-5 (minor triad)
C7 = 1-3-5-b7 (dominant 7th)
Cmaj7 = 1-3-5-7 (major 7th)
Cm7 = 1-b3-5-b7 (minor 7th)
Cdim = 1-b3-b5 (diminished: two stacked minor 3rds)

Practice Exercise

Take the C major scale on your ukulele: C, D, E, F, G, A, B. Build triads by stacking every other note. Start on C: play C, E, and G together. Move to D: play D, F, and A. On G: play G, B, and D. Each is a triad built from the scale - and they're all chords you already know. The construction is always the same: 1st, 3rd, and 5th of the scale starting on that degree.

Questions and Answers

What is the difference between a major and minor chord?: A major chord is built from the 1st, 3rd, and 5th degrees of the major scale (intervals: major 3rd + minor 3rd). A minor chord flattens the 3rd by one half step (intervals: minor 3rd + major 3rd). The single half-step difference in the 3rd creates the bright vs. dark quality contrast between major and minor chords.
What does "7th chord" mean in music?: A 7th chord adds a fourth note - the 7th scale degree - to a basic triad. The type of 7th (major, minor, or dominant) changes the color of the chord. A dominant 7th (e.g., G7) creates tension that strongly resolves to the tonic chord. A major 7th (e.g., Cmaj7) has a smoother, jazzier sound.

Next up: Chord Inversions: Smoother Voice Leading - developing the ability to recognize these intervals and chord qualities by sound alone.