Major Diatonic Chords — Complete Guide to Building Chords in Major Keys

A clear, structured explanation of how diatonic chords are built in major keys, using only the notes of the scale. This guide walks through the major scale pattern, stacking thirds, identifying chord qualities, and understanding Roman numeral notation — giving musicians a solid foundation in functional harmony.

Inside you’ll learn:

• What “diatonic” means and why these chords naturally belong to a key
• How the major scale is constructed using the pattern W–W–H–W–W–W–H
• How triads are formed by stacking thirds on each scale degree
• The full set of major‑key diatonic triads:
• I – Major, ii – minor, iii – minor, IV – Major, V – Major, vi – minor, viiº – diminished
• How Roman numerals distinguish chord qualities and make progressions key‑independent
• Practical uses of diatonic chords in songwriting, arranging, improvisation, and functional harmony

This sheet also includes worked examples in C major and D major, showing how diatonic chords translate across keys and how progressions like I–IV–V adapt simply by knowing the scale degrees.

Perfect for guitarists, pianists, arrangers, and students who want a concise, reliable reference for major‑key harmony.