How to Build Major, Minor, Diminished & Augmented Triads

Learn the four triad qualities — major (M3+m3), minor (m3+M3), diminished (m3+m3), augmented (M3+M3) — and how to build them on any root note.

What Is a Triad?

A triad is a three-note chord built by stacking two thirds on top of a root note. Every chord in Western harmony is either a triad or a triad with added notes. Master triads first, and seventh chords and extended harmony will follow naturally.

Major Triad = M3 + m3

Root to third = major third (4 half-steps). Third to fifth = minor third (3 half-steps). Example: C-E-G. Sounds bright, happy, resolved.

Minor Triad = m3 + M3

Root to third = minor third (3 half-steps). Third to fifth = major third (4 half-steps). Example: C-Eb-G. Sounds dark, sad, emotional.

Diminished Triad = m3 + m3

Root to third = minor third. Third to fifth = minor third. The fifth is a tritone from the root. Tense, unstable, wants to resolve.

Augmented Triad = M3 + M3

Root to third = major third. Third to fifth = major third. The fifth is an augmented fifth from the root. Bright but unsettled — listen for it in suspense film scores.