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Let’s say you are the Batman of songwriting. You have all the moves. Your chords, scales, pentatonics, knowing how to write melodies, etc are your kicks, punches, chokeholds, grapples, etc. 

Another huge tool in your belt must be to be able to do Roman Numeral Analysis. Why? Because it will help you make sense of the chord progressions in songs, so this is an invaluable skill to have. It’s Batman’s ability to assess a situation and act strategically. 

Ok enough with the Batman reference, you get the idea. But what is this analysis we speak of?

What is Roman Numeral Analysis?

Roman Numeral Analysis is a system for analyzing the harmonic structure of a song by identifying what chords make up the chord progression, what key they fall into, and assigning each chord a Roman Numeral from one to seven depending on the scale degree the chord is built from.

In plain english, you put a number from 1-7 to each chord in a key, then look at what the combination of numbers is in your chord progression in that key.

How To Do Roman Numeral Analysis (Simple Explanation)

Let’s look at the example below and you’ll see how simple this actually is. First we have our chords. To keep things simple I’m going to just go ahead and tell you this progression is in the key of C.

Song chords (we know it’s in the key of C):

Cmaj, Gmaj, Amin, Fmaj

So we know the key is C. All the possible chords in the key of C (in order) are the below:

Cmaj, Dmin, Emin, Fmaj, Gmaj, Amin, Bdim

Since Cmaj is the first chord (of the C Major key), it is the “one” chord. Dmin would be the “two” chord, and so on. So let’s use Roman Numerals to label them. 


Cmaj, Dmin, Emin, Fmaj, Gmaj, Amin, Bdim

Major vs Minor chords in Roman Numerals

Now, how do we label Major chords differently from Minor chords so we know which is which? Well Major chords will be uppercase and Minor chords will be lower case.

Major Key Formula in Roman Numerals

I – ii – iii – IV – V – vi – viio

Cmaj, Dmin, Emin, Fmaj, Gmaj, Amin, Bdim

As you can see some of the chords are Major and some are Minor and that last chord is diminished. This Roman Numeral formula is the same for ALL Major keys and each chord in the key has a number assigned to it. 

Back to our example chord progression. Let’s analyze it. 

We just have to check what the chords of the progression were and see what numeral they have in the key of C Major. 

Cmaj, Gmaj, Amin, Fmaj

I – V – vi – IV

And there you have it. You just did Roman Numeral Analysis. BOOM. 

This is of course a very simple example, but I want you to wrap your head around it easily. It can get more complicated than this when it comes to analyzing chord progressions that are not all in one key. But that’s a topic for another day.

What if you don’t know the key of the song?

If you’re reading this article I assume you’re just getting acquainted with music theory, so I really don’t want to bog you down with tons of theory in one post because it might just confuse you. I’d rather make a separate article on how to find the key of a song. So stay tuned and I’ll probably link it here later if you do want to go deeper. 

Two quick hacks for finding the key of a song

  1. A good rule of thumb for many many modern songs is that the first chord of the song will likely be the key of the song. So if the first chord is Cmaj, it’s highly likely the key is C Major for the whole or most of the song. 
  2. In some songs they might use the root chord of the key as the first chord in the chorus though, so that’s another possibility. 

They do this because putting the root chord of the key at the beginning of the song sets the tone for the rest of the song so the rest of the chords feel like you are “departing” from that feeling of home. 

When the root is in the first chord of the chorus, the intention is to make you feel like you arrived home when you hit the chorus. It helps emphasize that it is the main idea/point/message of the song. 

Songs with borrowed chords or key changes

Sometimes there may be 1 or two chords that don’t fall into the key of the first chord of the song, but that could just be a chord borrowed from another key or there might be a key change for the bridge of the song. This is pretty common. 

What you want to look out for is, which chord feels the most like “home”, like that feeling that you arrived where you were trying to go with your chords. 

So those are some things that can give you a quick general idea of what the key of the song might be. You can always Google what the chords are for the key you think it is and see if most of the chords are in it. 

Like I said, I’ll make a separate article about finding the key that will go deeper and be more helpful. Stay tuned. 

What Do The Symbols Mean in Roman Numeral Analysis?

Roman Numeral Analysis uses symbols to indicate certain aspects of a chord in a progression. It can tell you things like whether it is Major, Minor, Seventh, Dominant, Augmented, or Diminished. 

Here are the symbols and what they mean:

  • Uppercase Roman Numeral (such as IV) means it’s a Major triad chord.
  • Lowercase Roman Numeral (such as ii)means it’s a Minor triad chord. 
  • A superscript “o” (such as viio) means the chord is Diminished.
  • Uppercase Roman Numerals with a “+” sign (such as V+) means it’s an Augmented chord. 
  • Uppercase Roman Numeral chords with a superscript “7” (such as V7) means it is a Dominant 7th chord. 
  • Lowercase Roman Numeral with a “7” (such as ii7) means it is a Minor 7th chord
  • Lowercase Roman Numeral with a “” (such as vii7) means half diminished and “o” (such as viio7) means fully diminished.

Difference Between Roman Numeral Analysis and the Nashville Number System?

Roman Numeral Analysis and the Nashville Number System both serve the same purpose, which is to help analyze the chords in a song. The key difference is that the Nashville Number System uses Arabic numbers (like 1, 2, 3) instead of Roman numbers (I, II, III). This is to make it easier to communicate between musicians as Arabic numbers are more commonly used than Roman numerals in everyday life.

They also have slightly different symbols such as using a “minus” sign (-) or a lowercase “m” to indicate a chord is minor. The Nashville Number System is a shorthand. It’s like slang for Roman Numeral Analysis to make it easier to read and communicate. 

What Do The Symbols Mean in the Nashville Number System?

The Nashville Number System uses many of the same symbols as Roman Numeral Analysis to describe chords. These are:

  • A number with no symbols (such as 2) means it’s a Major triad chord.
  • A number with a “-” symbol or a lowercase “m” (such as 2m) means it’s a Minor triad chord. 
  • A superscript “o” (such as 7o) means the chord is Diminished.
  • A number with a “+” sign (such as 5+) means it’s an Augmented chord. 
  • A number with a subscript “7” (such as 57) means it is a Dominant 7th chord. 
  • A number with a dash and a superscript “7” (such as 2-7) or an “m” and superscript 7 (such as 2m7) means it is a Minor 7th chord. 
  • A number with a “” (such as 7) means half diminished and “o” (such as 7o7) or “dim” (such as 7dim) means fully diminished.

Why Roman Numeral Analysis is Important for all Musicians

This might help you if you are just getting into music theory and want to know why you should even bother learning it in the first place. When we understand why it’s important, it helps us open up to it so it doesn’t feel like it’s such a chore, and feels more like learning a cheat code to make your life easier. 

Roman Numeral Analysis is important because it is a tool for analyzing the chords of a song. It allows us to label and understand the relationships between chords in chord progressions and musical compositions.

This can help us understand why songs and compositions work or don’t work to create better songs and chord progressions that flow seamlessly. It also helps to communicate how a song is written to other musicians and collaborators in the studio or while practicing for a gig. 

Analyzing The Building Blocks of A Song

The first (and arguably the biggest) benefit of understanding Roman Numeral Analysis is because it helps you analyze how the chords are building the song depending on what key the song is in. 

You’d be surprised how logically many songs are built. Simple songs can often be formulaic and mathematical. You can see this in a lot of pop songs which tend to stay in one key, use common chord progressions and often have a very cookie cutter structures. 

With Roman Numeral Analysis we can assign numbers to the chords used in a song. So we could say a song is using for example, the first, fifth, sixth, and fourth chord of a Major key in that order. 

This is actually a really common combination. It’s known as the Pop Song Chord Progression. 

It’s not the only one though, there are many combinations that have become common chord progressions and knowing Roman Numeral Analysis helps us see those common combinations. It lets us see the building blocks of a song as far as chords go. 

Analyzing Patterns in an Artist’s Sound

An artist “having a certain sound” could mean a lot of things. It could mean their production, the instruments they use, their stylistic preferences in how they play their instruments…AND it can also mean that they use the same chord progressions in multiple songs but in different keys (so we don’t notice). 

Sometimes specific changes from one chord to another in progressions can become a part of their sound and with Roman Numeral Analysis we can see those patterns in an artist’s chord progressions. This gives us insight into their sound and their songwriting choices.

Analyzing Historical Periods or Genre-wide Patterns

Another big benefit of Roman Numeral Analysis is this insight can help pinpoint specific patterns in an entire historical period (like with Baroque classical music) or an entire genre (like with Pop music or Jazz). 

Being able to see these patterns allows us to appreciate the differences and nuances of each era and genre.

Helps to Teach Music

Roman Numeral Analysis is a great tool to teach people music. It’s really a huge communication tool so that not only can you understand how a song is built, but you can teach someone else about it. 

This is obviously helpful for a teacher and student of music, but it can also be helpful for teaching bandmates, producers or other collaborators how a song is built so that you can play it together, or work on improving it together. So all musicians can benefit from this.

Helps to Write Better Songs

In addition to understanding a song, my favorite benefit is being able to use this type of analysis to write better songs. 

How does it help you write better songs?

  • Identify and troubleshoot Chord Functions: You can see how the chords are flowing from one to another and see if there are issues with chord functions (how seamlessly chords flow into each other). If you’re unfamiliar with this concept check out this post Chord Function: The Compass to Flowing Chord Progressions
  • Identify overused chord progressions: If you write a lot of songs you might start to use the same chord progressions for each one but just in different keys. While there is nothing wrong with this, if you overdo it, your songs will all start to sound the same. You might not know why until you realize it’s because you’re doing the same thing in different keys too often. 
  • Identify what chords you could substitute for other chords: This could mean changing one of the chords from major to minor or vice versa. It could also mean changing one of the chords for a chord from a mode (if you don’t know about this check out this article How to Write Songs Using Modes

Wrapping it up

As you can see, learning Roman Numeral Analysis is VERY helpful. This is one of those concepts that serves as a main pillar in your understanding of music and your improvement as a songwriter/composer. 

This will bridge the gap between theory and practice as you write songs so make sure you don’t skip it.

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