The IV chord
Roman numerals in music refer to chords based on scale steps. The IV chord can mean different things depending on the actual musical key. In the key of C major, the IV chord is F.
Chords and intervals
The table shows how scale steps and chords are related in the key of C:
| Scales steps | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|
| Roman numerals | I | ii | ii | IV | V | vi | vii |
| Chords | C | Dm | Em | F | G | Am | Bdim |
The fourth scales step is F, which result in the F chord. The fourth note of a scale is also referred to as the subdominant.
Whereas the fourth degree is major in the context of the Major scale, the fourth degree is minor in the Minor scale. For example, Fm (iv) in the C Minor scale. Another example is F#dim (iv#) in C Lydian mode.
The IV chord in all keys
The IV chord is identical with the fourth degree of the key, a list of the fourth chord would look like this:
C major key = F major
C# major key = F# major
D major key = G major
D# major key = G# major
E major key = A major
F major key = A# major
F# major key = B major
G major key = C major
G# major key = C# major
A major key = D major
A# major key = D# major
B major key = E major
So, for example, in the key of G#, the IV chord will be C#.
The iv chord in all keys
A similar set of relationship can be seen for the minor keys:
A minor key = Dm
A# minor key = D#m
Bm minor key = Em
Cm minor key = Fm
C#m minor key = F#m
Dm minor key = Gm
D#m minor key = G#m
Em minor key = Am
Fm minor key = A#m
F#m minor key = Bm
G minor key = Cm
G# minor key = C#m
So, for example, in the key of D# minor, the iv chord will be G#m. The iv degree is sometimes written as IVm.
The IV chord in progressions
The benefit with Roman numerals is that chord progressions can be transposed to other keys. One of the most played progressions of all is the I - IV - V progression with the tonic, the subdominant and the dominant degrees. A similar variation is I - V - IV, that is also extremely common.
These can also include extended chords: Dmaj7 (Imaj7) - G6 (IV6)
- A7 (V7); Emaj7 (Imaj7) - B11 (V11)
- Amaj7 (IVmaj7).
See also Chord theory | Music theory.
