Roman Numeral Analysis is an invitation to start thinking about and listening to chords in functional harmonic terms…
We must also understanding how a chord functions in a particulate context.
To that end, a common practice for describing chords in functional harmonic terms is to analyze them using Roman Numerals.
The Roman Numeral naming convention works like this…
- Chords are named using the MAJOR SCALE as the point of reference.
- Each chord is assigned a number based on which note the root of the chord falls along the scale degrees of the major scale.
- Major chords use upper-case Roman Numerals.
- Minor chords use lower-case Roman Numerals.
- Diminished Chords use lower-case Roman Numerals with a “degrees” symbol (°) immediately following.
- Note: Other chord types are possible and will be discussed as they arise in context.
Roman Numeral Analysis for the Major Scale…
All seven diatonic (within the key signature) triads of the C Major scale named using Roman Numeral notation (scale degrees shown in the bass)…

In major keys, the I chord establishes both the tonic note and major-ness of the key, while all of the other chords create unique tensions with respect to that key center.
Roman Numeral Analysis for the Natural Minor Scale…
All seven diatonic (within the key signature) triads of the C Natural Minor scale named using Roman Numeral notation (scale degrees shown in the bass)…

In minor keys, the i chord establishes both the tonic note and minor-ness of the key, while all of the other chords create unique tensions with respect to that key center.
Of course, there are other tonalities besides major and natural minor (Minor-Minor, Mixolydian, Dorian, Blues, etc)… as well as many other kinds of chords (seventh chords, suspensions, etc) and chord functions (secondary dominants, borrowed chords). It may seem like a lot know, but don’t despair. It will all become as you study real chord changes in context. For the moment it is enough to understand the Roman Numeral naming conventions and to start thinking about chords in functional terms.