A guitar chord is more than a shape on the fretboard. It is a group of notes chosen for the way their pitches relate to one another. Those relationships are called intervals, and chord formulas describe them using scale degrees. Once you understand this system, you can work out how major and minor chords are built, find notes across the neck, and make sense of chord names instead of relying only on memorized fingerings.
Start With Intervals
An interval measures the distance between two notes. On a guitar, moving one fret raises a note by one half step; two frets make a whole step. For example, if you start on C, the note one fret higher is C-sharp, and the note two frets higher is D. This fret-by-fret pattern makes the guitar a practical place to see and hear how intervals shape a chord.
Chord formulas count notes in relation to a root, the note that gives the chord its name. Scale degrees provide a simple way to label those relationships. The root is 1, the next scale note is 2, and so on. In a chord formula, a number such as 3 or 5 refers to a scale degree above the root, not a particular fret or string.
Build a Major Chord
A basic major chord, also called a major triad, uses the formula 1–3–5. Starting with C, the major scale notes are C, D, E, F, G, A, and B. The first, third, and fifth notes are C, E, and G, so C major contains those three notes. The distances are a major third from C to E and a minor third from E to G.
You can also build a major triad by counting from the root: move four half steps to find the major third, then three more half steps to find the fifth. From C, that gives E and G. On guitar, you may play some of these notes in more than one octave, or double a chord tone on another string. The chord remains C major as long as its essential notes still establish that sound.
Build a Minor Chord
A minor triad uses the formula 1–♭3–5. The flat sign means to lower the third scale degree by one half step. For C minor, begin with the C major scale: C, D, E, F, G, A, B. Lower E to E-flat, while keeping C and G. The result is C, E-flat, and G.
The interval pattern explains the difference in sound: a minor third spans three half steps from the root, followed by a major third spanning four half steps. To make C minor from C, count three half steps to E-flat, then four more to G. Compared with C major, only the middle note changes. That small adjustment is why learning chord formulas can help you adapt familiar shapes and recognize chord quality by ear.
Apply the Formulas on Guitar
To test a formula on the fretboard, first name the root note, then locate the other chord tones using the interval distances. Check each note you play against the formula. A common open C major fingering, for instance, includes C, E, and G, with some notes repeated. You do not need every note in root-position order; guitar voicings often arrange chord tones differently for a comfortable shape or a particular sound.
Practice one root at a time and compare its major and minor versions. Play the major triad, lower its third by one fret, and listen for the change. Then find the same chord tones in another area of the neck. Ottawa Guitar Theory can help learners connect formulas to practical guitar playing, but you can begin on your own with a tuner, a fretboard diagram, and a few deliberate repetitions.
Intervals show the distances between chord notes, while formulas make those distances easy to describe. A major triad uses 1–3–5; a minor triad uses 1–♭3–5. Start with one root, find each note, and listen closely as you change the third. If you would like guidance applying these ideas to your playing, consider exploring a guitar theory lesson.