I, IV, V Progression & Song Writing

Songwriting is an important part of music production...obviously but before you learn how to form certain chords you must first learn about scales. 

A scale is a series of notes that go in an ascending and descending manner. For every scale that is minor or major there are 7 notes, for example in the key of C the notes are C - D - E - F - G - A - B. and the 8th note (in this example will be C) goes back to the root note but an octave higher. (the 12th fret on a guitar).

Each note of a scale has a corresponding number from 1 to 7. So for the key of C it will be as follows:

C = 1
D = 2
E = 3
F = 4
G = 5
A = 6
B = 7

In order to make a major triad you will play the 1st + 3rd + 5th notes of a major scale.

In our example it is C - E - G, that's the C major chord.

Let's have another example this time using the C minor scale:

C = 1
D = 2
Eb = 3
F = 4
G = 5
Ab = 6
Bb = 7

In order to make a minor triad you will play the 1st + 3rd + 5th notes of a minor scale.
In our example it is C - Eb - G, that's the C minor chord.

Roman Numerals

Sometimes instead of numbers Roman Numerals are used. We go back to our example and use a Roman Numeral for each note in the key of C:

C = I
D = ii
E = iii
F = IV
G = V
A = vi

Roman numeral I refers to the chord built on the first note of the C major scale. Roman numeral II refers to the chord built on the second note of the C major scale, and so on. If you notice, some of the Roman numerals are capitalized while others are not. Uppercase Roman numerals pertain to a major chord, while lowercase Roman numerals pertain to a minor chord. Uppercase Roman numerals with a (+) symbol refer to an augmented chord. Lowercase Roman numerals with a (o) symbol refer to a diminished chord.

The I, IV and V Chord Pattern

For each key there are 3 chords that are played more than others known as "primary chords." The I - IV - V chords are built from the 1st, 4th and 5th note of a scale.

Let's take the key of C again as an example, looking at the illustration above, you will notice that note I on the key of C is C, note IV is F and note V is G.

Therefor the I - IV - V chord pattern for the key of C is:
C (note I) = C - E- G (1st + 3rd + 5th note of the C scale)
F (note IV) = F - A - C (1st + 3rd + 5th note of the F scale)
G (note V) = G - B - D (1st + 3rd + 5th note of the G scale)

There are many songs that have been written using the I - IV - V chord pattern, just about every Beatles song, Elvis tune, greenday & most blues tunes.

Practice playing the I - IV - V chord pattern for every major key and listen to how it sounds as this might inspire you to come up with a great melody for your song.

Here's a handy table to guide you. Now get writing. I haven't heard anything awesome in about an hour.

I - IV - V Chord Pattern

Major Key - Chord Pattern
Key of C	C - F - G
Key of D	D - G - A
Key of E	E - A - B
Key of F	F - Bb - C
Key of G	G - C - D
Key of A	A - D - E
Key of B	B - E - F#
Key of Db	Db - Gb - Ab
Key of Eb	Eb - Ab - Bb
Key of Gb	Gb - Cb - Db
Key of Ab	Ab - Db - Eb
Key of Bb	Bb - Eb - F	....