The key of A Major contains the following chords:
These chords are formed by stacking thirds on each note of the A Major scale, so that we are left with seven three-note voicings (more about this later). This is the most common way to produce chords in any given key. However, we can also form chords by stacking thirds to produce four-note voicings (which are called 7th chords).
Chords in the Key of A Using 7th Chords
By using 7th chords (instead of triads), the seven chords in the key of A are:
- A Major 7
- B minor 7
- C# minor 7
- D Major 7
- E Major 7
- F# minor 7
- G# half diminished
Deriving Chords from the A Major scale by Stacking 3rds.
Because we are looking at the chords in the key of A, we naturally use the notes of the A Major scale to produce the chords. Here are the notes of the A Major scale.
- A, B, C#, D, E, F#, G#
When using triads (3-note voicings), we stack thirds on each of the seven notes of the scale to produce seven chords.
We can also do this same exercise, using four-note voicings (7th chords).
The process is the same, except now we stack notes in 3rds until we have four notes for each degree of the scale.
Roman Numerals in Key of A
It’s common to refer to chords in keys by using roman numerals. When representing chords with roman numerals, we use upper case for Major chords and lower case for minor chords. Here are seven chords, represented as roman numerals, in the key of A:
- I = A
- ii = Bm
- iii = C#m
- IV = D
- V = E
- vi = F#m
- vii = G#°