Memorizing Diatonic Chords Using Roman Numerals (Degree Names) / Music Theory Lesson

Author: sleepfreaks

Preparing the Ground Work Before Using Your Newfound Theory Knowledge

This time, we will be taking a look at how to change chords to roman numerals (degree names).

This is useful information for analyzing chord progressions in a song and makes diatonic chords more approachable,
so be sure to get the most out of this article!


Something that you should definitely begin practicing once you learn music theory is song analysis.
By analyzing parts of a song that you feel are “cool”, “satisfying”, or makes you feel a certain emotion,
you can add it to your chord library to use in your own work.

We will take you to this point one step at a time so stick with us to see it through!


The analysis chart we will use for reference can be downloaded from the URL below.

Taking a look at Diatonic Chord Rules

Though we have taken a detailed look at diatonic chords up until this point,
lets take a look back at the major diatonic chords (triad) of each key.


Memorizing every single one of these is an awful lot of work.
However, by understanding the major scale of each key,
you can use the technique of “changing chords to roman numerals” to easily understand them.

A chord that is changed with its roman numeral equivalent is called the “degree name” or “chord degree”.
This roman numeral represents the “degree” of the chord within a key.

The biggest factor is that no matter what key you make the diatonic chords,
they will have the same relation to the currently selected key scale.

  • Key = C Major
  • C_Diatonic

  • Key = D Major
  • D_Diatonic

As we can see, both follow the same pattern of
major, minor, minor, major, major, minor, diminished (triad).

In addition, like learned in our major minor and diminished articles, the chords can all be inter-lapped perfectly by moving them in your DAW.


Knowing this rule, this means that each scale degree can be swapped with a roman numeral number as well.

Applying Roman Numerals to a Scale

The roman numerals that are used are as follows.


Roman numerals are applied in progression from the starting point of the scale.



Lets make diatonic chords from these numerals. We can do so just like mentioned in our 17th article.
The type of chord will be depicted next to the roman numeral.

This completes it.
By using roman numerals to designate chords, you can input the notes of whatever major scale is selected to easily find out the diatonic chords (triads) of the key.

  • You may see a △ next to major or ⅲ for minor using degree names. For the purpose of these tutorials we will stick to the style shown above.

Using Degree Names

Lets try changing the scale name in the Key=F major.



By using what we have learned up until this point, its very easy to do.

In addition, the chords would be named as shown below:

  • I = one major
  • IIm = two minor
  • IIIm = three minor
  • IV = four major
  • V = five major
  • VIm = six minor
  • VIIdim = seven diminished (triad)

Last, we have included a list of major diatonic chords (triads) including roman numerals so please check it out from the link below.


Next time we will use these degree names for some simple analysis and taking a look at famous chord progressions
so stay tuned and be sure to study up on this article’s information!

Article Writer: Kazuma Itoh

講師 伊藤
After moving to the USA at 18 years of age with a scholarship from Berklee, he completed a 4 year study focused on song writing and arranging there.
Using this knowledge, he works across a variety of fields from pop music, film music, and more.