Welcome to our chord theory lesson. Chords are derived from scales. Below is the C major scale. Note that each note on the scale is given a number according to its position. This number is called the scale degree. For example, in the C major scale, G is the 5th degree.
A major chord is built using the 1st degree (also referred to as the root), the 3rd degree and the 5th degree of a major scale. Thus, C major chord consists of notes C, E and G as shown below.
A minor chord is built using the 1st degree, the flatted 3rd degree and the 5th degree of a major scale. Therefore, chord C minor consists of notes C, Eb (E flat) and G.
To create a 7th chord, you use the 1st, 3rd, 5th and flatted 7th degrees of a major scale. In the example below, you will notice that notes C, E, G and Bb make up chord C7.
A minor 7th chord is constructed using the 1st, flatted 3rd, 5th and flatted 7th degrees of a major scale. Thus, Cm7 chord is made up using notes C, Eb, G and Bb as shown below.
To build a major 7th chord, you use the 1st, 3rd, 5th and 7th degrees of a major scale. The example below shows you how chord C Major 7 is built using notes C, E, G and B.
A 9th chord is an extension of a 7th chord. You build a 9th chord using the 1st, 3rd, 5th, flatted 7th and 9th degree of a major scale. Thus, chord C9 consists of notes C, E, G, Bb and D.
A major 9th chord is an extension of a major 7th chord. You create it using the 1st, 3rd, 5th, 7th and the 9th degree of a major scale. The circled notes below make up chord C Major 9.
A minor 9th chord is an extension of a minor 7th chord. Use the 1st, the flatted 3rd, 5th, flatted 7th and the 9th degree of a major scale to create a minor 9th chord. Below are the notes of chord C minor 9 (C, Eb, G, Bb and D).
Conclusion
Although this chord theory article does not cover every chord formula, it is a good foundation for beginners to understand how chords are built. If you have any questions please do not hesitate to comment and I will reply. Want to learn more about how chords are constructed? Watch this helpful video for another explanation of chord theory.