The major triad formula: 1–3–5
A major triad stacks two thirds on its root: a major third (4 semitones) from the root to the third, then a minor third (3 semitones) from the third to the fifth. Together they span a perfect fifth (7 semitones) from the root. In C, C to E is 4 semitones, E to G is 3 and C to G is 7.
That fixed pattern of distances is why a major triad has the same bright, stable sound in every key: only the starting note changes.
Spell it with every other letter
The three notes of a triad always use every other letter name: C–E–G, F–A–C, G–B–D. When the root has a sharp or a flat, the other notes keep their letters and take whatever sharp or flat the formula needs. That is why B major is B–D#–F# and not B–Eb–Gb, and why the triad on Gb is Gb–Bb–Db.
Major triads in all 12 keys
The table follows the cycle of fourths, the same order GuitarPlan uses for its practice sessions.
| Key | Root (1) | Third (3) | Fifth (5) |
|---|---|---|---|
| C | C | E | G |
| F | F | A | C |
| Bb | Bb | D | F |
| Eb | Eb | G | Bb |
| Ab | Ab | C | Eb |
| Db | Db | F | Ab |
| Gb | Gb | Bb | Db |
| B | B | D# | F# |
| E | E | G# | B |
| A | A | C# | E |
| D | D | F# | A |
| G | G | B | D |
Why practice them in fourths
Each key in the cycle is a perfect fourth above the one before: C, F, Bb, Eb, Ab, Db, Gb, B, E, A, D, G and back to C. Following it, you meet all twelve roots once, and each new root is the IV chord of the key you have just practiced. Consecutive triads also share a note: the fifth of each new triad is the root of the previous one, as C–E–G and F–A–C share their C.
From notes to the neck
Knowing the notes is the first half. The second is finding them on the fretboard in their three possible orders, the triad inversions, on each set of three strings: see how to play triads on guitar.