How to build chords from scales
Scales and chords are related and chords are “built” from scales. Knowledge about scales is great for your understanding of chords and vice versa. In this article, we shall look at how chords are built from scales. By knowing this you don’t always have to memorize all the tones in different chords, instead you can rely on your knowledge to figure out by which tones chords are constructed.
The major and minor scales are the foundation for most chords
By knowing the major scale and the (natural) minor scale you will be able to envision a large part of all chords. Chords are constructed by tones that are included in these scales and ordered by certain intervals.
Different chord categories based on a major scale
As an example, here are some of the chords built on C Major scale:
All of these uses C note as the root and thereupon more tones from the C Major scale:
C: the root (C), major third (E), perfect fifth (G).
Cmaj7: the root (C), major third (E), perfect fifth (G), major seventh (B).
Cmaj9: the root (C), major third (E), perfect fifth (G), major seventh (B), major ninth (D).
These are far from all chords that can be built from a C Major scale, but some of the more common. In cases there the ninth is used as an interval, the chord include tones from two octaves (an octave is eight tones, such as the C Major illustrated on the diagram above).
If you wonder about names like major third, major fifth, perfect fifth and so on, this is terminology of different intervals.
The lesson from this is partly that you could use the same intervals and creating chords in other keys based on that particular major scale. For example, from D Major scale the corresponding D, Dmaj7, Dmaj9 and so on could be built with the same intervals.
All maj7 chords, for example, are built with a root, major third, perfect fifth and major seventh. What differs is the tones depending on the key or scale.
Different chord categories based on a minor scale
For a second example, here are some of the chords built on A Minor scale:
All of these uses A note as the root and thereupon more tones of the A Minor scale:
Am: the root (A), minor third (C), perfect fifth (E).
Am7: the root (A), minor third (C), perfect fifth (E), minor seventh (G).
Am9: the root (A), minor third (C), perfect fifth (E), minor seventh (G), major ninth (B).
As with the example with C major scale the same intervals are used for creating chords in other minor keys based on particular scales. For example, from B Minor scale the corresponding Bm, Bm7, Bm9 and so on could be built with the same intervals.
Chords with a different root tone based on a major scale
So far, we have looked at how chords with the same root chord could be constructed from a scale. We will now expand into chords with different root tones, but still only use one scale for the building blocks.
Again, we use the C Major as an example and these are several triads built on the scale:
All of these uses tones of the C scale:
C: C, E, G
Dm: D, F, A
Em: E, G, B
F: F, A, C
G: G, B, D
Am: A, C, E
Bdim: B, D, F
All chords besides Bdim are either major or minor triad, with the intervals already mentioned above. In Bdim the intervals are: root (B), minor third (D), diminished fifth (F).
Chords with a different root tone based on a minor scale
Finally, we shall look at the same thing with chords based on the minor scale.
Again, we use A Minor as an example and these are several triads built on the scale:
You may already have noticed that A Minor is relative to C Major, therefore the chords are the same.
So to summarize, lots of chords are based on the major and minor scales. The chords mentioned in the examples are only a few.