Roman Numeral Analysis vs Nashville Number System

Explaining the differences between the two chord numbering systems

As musicians, we tend to refer to the same thing in multiple ways. This can vary even more from instrument to instrument. We develop our own instrument “colloquialisms” (did not nail the spelling my first try) that don’t always translate well.

This is the primary reason sheet music works so well. It’s clear, with no room for interpretation. There are a couple problems with sheet music though:

  •       Not everyone reads it (looking at you guitarists)
  •       It’s not practical for all situations (cover bands, Sunday mornings)
  •       Most musicians really just need the chords (and can fill in the rest)

You’re probably inferring, that I’m implying, (and now I'm stating) that chord charts are a better solution in most cases.

And you’d be right. But not just any chord chart.

Let’s say you have a capo’d rhythm guitar and a bass in your group. How many chart variations would you need to write out? More than one, which is too many. The guitarist with the capo will be playing in a different “key” (different shapes) so the chart used by the bassist would be useless.

The better solution is using either the Roman Numeral Analysis or Nashville Number System. One chart can be used by every musician (even drummers, especially with the Nashville Number System), in any key. Even if that key changes during rehearsal.

The reason in both cases is we’re replacing the actual chords (like C-G-Am-F) with some sort of numeric representation. If you have basic understandings of the Major scale, these are actually very easy to read. And provide greater performance direction in the case of the NNS.

Let’s take a look at each system and find out what exactly they are, and which one might be the best for your application.


Understanding The Roman Numeral Analysis

Let’s start with a touch of music theory. Don’t panic, basic music theory is just elementary level math. Each note in a scale can be linked to a number, which represents its position in the scale.  Looking at the C Major scale:

C is 1

D is 2

E is 3

F is 4

G is 5

A is 6

B is 7

When we look at the above, we can see the C note is the first note (or degree) in the scale. The D is the second degree in the scale, and so on. This is how we make up our chords, by combining notes intentionally.

All Chords in a key also have numeric representation. And you guessed it, C is the one chord, D is the two chord, etc. There's one change though; when we talk about chords in a key, we switch to Roman Numerals:

C is I

D is ii

E is iii

F is IV

G is V

A is vi

B is viiº

You may have noticed that some are upper case and some are lower case. It’s not because I’m a lazy typer. Though that’s a fair assumption. The uppercase Roman Numerals represent Major chords, and the lowercase Roman Numerals represent minor chords. The last chord (the seven chord/viiº chord) is a diminished chord, which is still considered minor.

This holds true for any Major key. The one, four, and five chords are always Major (the I, IV, and V chords). The two, three, and six chords are always minor (the ii, iii, and vi chords). The seven chord is always a diminished chord (the viiº chord).

If you play C-G-Am-F, you’d call that a I-V-vi-IV pattern. AKA, every Pop Punk song since 1998.

You’ll see these commonly used in place of the named chords on a chord chart. Here’s an example for a song I just wrote:

Instead of listing the chord names, you’re using the numbers. If you know your major scales you can identify the actual chords based on the key. I’m using Fmaj7-G-Em-Am. The IV(maj7), V, iii, and ii in the key of C Major. Your chord extension notations carry here too. You'd add a 7, 9, 11, 13, +, -, etc as you would for notating specific chords.

The best application for this is in a group where everyone knows the song. Churches, cover bands, jam sessions. You’re not looking for nuance, just a guide with extreme key flexibility.


Understanding The Nashville Number System

A lot of the time when people see the Roman Numerals, they call that the Nashville Number System. The idea is similar, but also much different.

The Nashville Number System uses the numbered chords (like 1-5-6-4) instead of Roman Numerals. But it uses a lot of symbols to easily identify what you’re playing. For example, you might see:

1  5 -6 4

In the key of C Major, that would be C-G-Am-F. That minor chord isn’t notated “Am”, but rather “-6”. Normally we’d see the dash as signifying diminished in traditional music. But the NNS uses various symbols to identify chords. Here are the common ones:

This takes some adjusting, but for most musicians and songs you’ll only see minor and seventh chords. The other common chord notation will be the inversion. In the key of C major again, you may see 1/3 (or C/E - C major with an E in the bass).

Much like the Roman Numeral Analysis, this makes it very easy to change keys on the fly. Which is very important to do as a session musician. You’re able to learn new songs with a single run through. Not only that, but this same chart can be used by any musician who walks through the door. Guitarists, Bassists, Drummers, Mando/utility players, keyboards.

(this is also a great and quick way to transcribe songs you’re learning by ear)

Here’s a quick run through of how to read a Nashville Number Chart. Using the same song I totally just made up earlier as an example, here’s what the NNS chart would look like:

The key, time signature, and tempo are all written out. You’d also find the song title up at the top, if I had named it yet. The 4 chord has the major 7 notation, and the 3 and 6 have the minor indications. In the key of C you’d play Fmaj7-G-Em-Am.

Each chord written is played for one measure, unless one or more are underlined. In this example, the 4 and 5 chord consume one measure, and the 3 and 6 consume one measure. You might find three or even four chords underlined. You’d play all of them in a single measure. If the chord is not underlined, the single chord would be played for a measure.

Unless otherwise notated, you can assume the chords are split evenly. The notations get a little more complicated when talking about timing. For today, we won’t delve too far into that.

Here’s a really cool video by Harry Miree explaining (and demonstrating) just how this whole thing works practically. He’s a killer drummer, and this shows how accessible the system is for ALL musicians.



And a live playthrough of a song with the charts:



Which Chord System Is Better?

I love both of them. If I'm listening to a song with a really cool progression, I might write that down using the Roman Numerals to play around with later. Since I'm just using relative pitch to identify the chord pattern, I’m not concerned about the key. Plus I'll probably try it in a couple different keys to utilize different chord voicings.

If someone’s telling me “here, learn these songs for rehearsal next week”, I’m hoping that presumptuous attitude that I have a ton of free time comes with some Nashville Number Charts.

Both are great ways for us non-sheet music reading musicians to learn songs quickly. Both of them push us to be better musicians. Both are highly valuable to have in our pockets.


Using Nashville Numbers and Roman Numerals In Chord Chart Apps

A lot of chord chart apps will give you the option to use Nashville Numbers or Roman Numerals.

Popular apps like OnSong give you the options to use Roman Numerals or Nashville Numbers for your charts. 1Chart is an app dedicated to charting songs with Nashville Numbers.

If you’re not using a chord chart app that offers this feature, it’s worth re-evaluating.