Lesson 08 · All 12 keys

Major Chord Triad Trainer

Learn how a major triad is built one semitone-count at a time, then put it to work with two MIDI exercises: playing all 12 major chords around the circle of fourths, and a pleasant four-chord progression in every key.

How a major triad is built

A triad is a 3-note chord. Every major triad — in any of the 12 keys — is built the exact same way, by counting semitones to the right from a root note:

  1. Start on the root — the note that names the chord.
  2. Count 4 semitones to the right to land on the major 3rd.
  3. From there, count 3 more semitones to the right (7 semitones from the root) to land on the perfect 5th.
Example — C major: start on C, count 4 semitones right to reach E, then count 3 more semitones right to reach G. C‑E‑G is the C major triad. The pattern 4 then 3 (7 semitones total from root to top) is what makes a triad "major" — every one of the 12 major chords is this same shape, just moved to start on a different key.

Try it: pick a root and build the chord step by step

Step 1 of 3
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Chord toneNoteSemitones from rootMIDI #

All 12 major triads at a glance

ChordRoot+4 semitones → 3rd+3 semitones → 5th

This MIDI exercise plays all 12 major chords, one after another, moving around the circle of fourths — each chord's root sits a perfect 4th (5 semitones) above the last one: C → F → B♭ → E♭ → A♭ → D♭ → G♭/F♯ → B → E → A → D → G → back to C. Every chord is played as a full triad (root, 3rd, and 5th together).

Chord 1 of 12
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The 12 chords, in circle-of-fourths order

#ChordRoot3rd5th

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Key of C
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Progression in C

DegreeChordRoot3rd5th