Guitar Start Guide
Once you understand how guitar chords are built, they stop being random finger shapes you memorise and start being logical things you can predict. Nearly every chord you play as a beginner is a “triad” — just three notes stacked in a specific way. Learn that one idea and major, minor, and diminished chords all make sense, and you’ll finally see why the shapes look the way they do.
This guide breaks down the triad formula, where the notes come from, and how the same three-note recipe produces very different-sounding chords.
What a triad is
A triad is a chord made of three notes: a root, a third, and a fifth. The root is the note the chord is named after (the root of a C chord is C). The third and fifth are picked out of the scale by counting. Those three notes are the entire chord — when you strum a six-string open chord, you’re usually just playing those same three notes, with some of them doubled in different octaves. If the numbering is new to you, our guitar music theory for beginners guide sets it up.
Stacking thirds: the recipe
Triads are built by “stacking thirds” — you take a scale, start on a note, then skip every other note. Take the C major scale (C D E F G A B) and build a chord on C:
- Start on C (the root).
- Skip D, take E (the third).
- Skip F, take G (the fifth).
C-E-G is a C major chord. Do the same starting on any other scale note and you get that note’s chord. This is exactly why knowing the major scale on guitar makes chords feel obvious rather than arbitrary.
Major, minor, and diminished
The distance between the root, third, and fifth is what gives a triad its flavour. Change the third by one fret and the whole mood flips. Here’s the summary:
| Triad type | Formula | Sound | Example |
|---|---|---|---|
| Major | Root + major 3rd + perfect 5th | Happy, bright | C-E-G |
| Minor | Root + minor 3rd + perfect 5th | Sad, moody | C-E♭-G |
| Diminished | Root + minor 3rd + flat 5th | Tense, unstable | C-E♭-G♭ |
The only difference between C major and C minor is one note dropping a single fret. That one-fret change is the whole story behind major vs minor chords — same root, same fifth, different third.
Every key has a set of chords
Build a triad on each note of the major scale and you get the seven chords that belong to that key. In C major they are: C, Dm, Em, F, G, Am, and B diminished. The pattern of major/minor/diminished is the same in every key: major, minor, minor, major, major, minor, diminished. This is gold for beginners because it tells you which chords are likely to appear in a song before you’ve even heard it — the foundation of every chord progression.
Why open chord shapes look the way they do
An open C chord uses five strings, but if you name the notes you’ll find only C, E, and G repeated. Guitar chord shapes double notes to make them sound full and to fit comfortably under the hand — but underneath, it’s still just the triad. Once you see that, “why does this shape work?” turns into “of course it does”. Knowing your notes on the fretboard lets you verify this for any chord you play.
Where to go next with chords
Triads are the foundation. Add a fourth note on top and you get seventh chords — the richer, jazzier sounds you’ll meet next in what are seventh chords. If you want to zoom out to the whole learning path, browse our guitar basics hub.
Frequently Asked Questions
What is a triad in guitar?
A triad is a three-note chord made of a root, a third, and a fifth. Most basic guitar chords are triads, even when the shape uses more than three strings — the extra strings just double the same notes.
What’s the difference between a major and minor chord?
Only the third. A major chord has a major third; a minor chord lowers that note by one fret to a minor third. The root and fifth stay the same, so the change is small but the mood shift is big.
Do I need to know triads to play songs?
Not to strum your first songs, no. But understanding triads makes learning new chords far faster and helps you see why certain chords fit together, so it’s well worth learning early on.
How do I build a chord from a scale?
Pick a starting note, then skip every other note twice to grab the third and fifth. For example, from C in the C major scale you take C, E, and G — a C major chord.