What Is a Triad in Music?

If you’re wondering what is a triad, here’s the short answer: a triad is a chord made of three notes stacked in thirds — a root, a third and a fifth. Triads are the most basic chords in music, and once you can build them, you can play and write most songs. This guide covers the four triad types and how to use them.

How a triad is built

Start on any note (the root), skip a note, add the next, skip again, and add one more. On C you take C, then E, then G — that’s a C major triad. The three notes are named the root (C), the third (E) and the fifth (G). The quality of the third and fifth decides what kind of triad you get. If interval names are unfamiliar, our guide to music intervals explains thirds and fifths.

The four types of triad

By adjusting the third and fifth, you get four triad qualities:

• Major triad — major third + perfect fifth. C–E–G. Bright and stable.
• Minor triad — minor third + perfect fifth. C–E♭–G. Darker, sadder.
• Diminished triad — minor third + diminished (flattened) fifth. C–E♭–G♭. Tense and unstable.
• Augmented triad — major third + augmented (raised) fifth. C–E–G#. Suspenseful, dreamlike.

The difference between major and minor comes down to a single note: the third. Lower the third of a major triad by a half step and it becomes minor. That one note is what your ear hears as happy versus sad, the same idea behind major vs minor scales.

Triads in a key

Build a triad on each note of a major scale and you get the seven diatonic chords of that key. In C major those are C (major), Dm, Em, F (major), G (major), Am and Bdim. The pattern of qualities — major, minor, minor, major, major, minor, diminished — is the same in every major key, which is why triads are the foundation of common chord progressions.

Inversions: the same triad, reordered

You don’t have to keep the root on the bottom. Move it up an octave and the third becomes the lowest note (first inversion); move the third up too and the fifth is on the bottom (second inversion). The chord is still a C triad — just voiced differently for smoother movement between chords. Learn more in chord inversions explained.

Frequently asked questions

Is a triad the same as a chord?

A triad is a type of chord — specifically a three-note chord built in thirds. All triads are chords, but not all chords are triads. Add a fourth note in thirds and you get a seventh chord; chords can also have more notes than three.

What happens when you add a fourth note to a triad?

Stacking one more third on top creates a seventh chord, like Cmaj7 (C–E–G–B). These richer chords are common in jazz, soul and R&B. See seventh chords explained for the details.

Which triad should beginners learn first?

Start with major and minor triads, since they make up the vast majority of chords in popular music. Once those feel automatic, add diminished and augmented triads to handle the trickier moments in songs.