Roman numerals are how musicians talk about chords without being locked to a single key. Instead of saying "C, F, G," a musician says "I, IV, V" and every player in the room knows exactly what to do, regardless of what key the song is in. That portability is why Roman numeral analysis is one of the most useful systems in all of music theory, and why it shows up in everything from classical harmony textbooks to pop songwriting circles.
This guide covers what Roman numerals mean in music, the chord chart for major and minor keys, how chord qualities and inversions are written, the most common chord progressions in Roman numeral notation, and how to add Roman numerals to a score inside your music notation software.
What are Roman numerals in music?
Roman numerals in music are a notation system for labeling chords based on their position in a key, not their absolute pitch. Each Roman numeral represents the scale degree the chord is built on (I for the first note of the scale, V for the fifth, and so on), and its case and symbols communicate the chord's quality (major, minor, diminished, augmented) and any extensions or inversions.
A I chord in C major is C major. A I chord in G major is G major. A I chord in F♯ minor is F♯ minor. Same Roman numeral, three different actual chords, all serving the same harmonic role. That's the point of the system.
How Roman numerals work
Three pieces of information are packed into every Roman numeral chord symbol:
1. The number tells you the scale degree. I is the chord built on the first note of the scale, ii is built on the second, iii on the third, and so on up to vii. In C major, that means I = C, ii = D, iii = E, IV = F, V = G, vi = A, vii° = B.
2. The case tells you the chord quality. Uppercase numerals (I, IV, V) are major chords. Lowercase numerals (ii, iii, vi) are minor chords. The diminished chord on the seventh degree of a major scale uses lowercase plus a small circle (vii°).
3. Symbols tell you alterations and extensions. A small circle (°) means diminished. A slashed circle (ø) means half-diminished. A plus sign (+) means augmented. A small 7 added (V7) means a seventh is added to the chord. Numbers like 6 or 6/4 indicate inversions.
Roman numerals chart for major keys
In any major key, the seven diatonic chords always follow the same quality pattern, regardless of the specific key. The pattern is: I, ii, iii, IV, V, vi, vii°. Three major chords, three minor chords, and one diminished chord.
| Scale degree | Roman numeral | Chord quality | Example in C major |
|---|---|---|---|
| 1 | I | Major | C major |
| 2 | ii | Minor | D minor |
| 3 | iii | Minor | E minor |
| 4 | IV | Major | F major |
| 5 | V | Major | G major |
| 6 | vi | Minor | A minor |
| 7 | vii° | Diminished | B diminished |
This pattern holds for every major key. In G major: I = G, ii = Am, iii = Bm, IV = C, V = D, vi = Em, vii° = F♯°. In D major: I = D, ii = Em, iii = F♯m, IV = G, V = A, vi = Bm, vii° = C♯°. Memorize the pattern once and you can apply it everywhere.
Roman numerals chart for minor keys
Minor keys add a small complication: there are three minor scales (natural, harmonic, melodic), and each one produces slightly different chord qualities on certain degrees. In practice, most analysis defaults to the natural minor for the base pattern, then notes when the harmonic or melodic minor borrows in.
Here is the pattern for the natural minor scale, which is the most commonly referenced:
| Scale degree | Roman numeral | Chord quality | Example in A minor |
|---|---|---|---|
| 1 | i | Minor | A minor |
| 2 | ii° | Diminished | B diminished |
| 3 | III | Major | C major |
| 4 | iv | Minor | D minor |
| 5 | v | Minor | E minor |
| 6 | VI | Major | F major |
| 7 | VII | Major | G major |
One detail worth knowing: in real-world minor-key music, the V chord is very often made major (capital V) by raising the seventh scale degree. This is borrowed from the harmonic minor scale, and it gives the V chord the strong pull back to i that we expect from cadences. So in A minor, you'll regularly see V (E major) instead of v (E minor), even though the natural minor pattern technically gives you the minor v.
Roman numerals reference chart (all keys)
For a quick reference you can keep alongside a score, here is the full Roman numerals chart across all keys, plus a downloadable PDF version.
Common chord progressions in Roman numeral notation
Most of popular music's recognizable chord progressions live inside a handful of Roman numeral patterns. Once you know these, you can hear a song, identify the progression, and play it in any key without learning new chords.
| Progression | Genre / use | Example songs |
|---|---|---|
| I–IV–V | Blues, rock, country, folk | "Twist and Shout," "Wild Thing" |
| I–V–vi–IV | Pop (the "axis" progression) | "Let It Be," "With or Without You" |
| vi–IV–I–V | Alternative pop, ballads | "Apologize," "Grenade" |
| ii–V–I | Jazz standard | The backbone of jazz harmony |
| I–vi–IV–V | 50s doo-wop, retro pop | "Stand By Me," "Heart and Soul" |
| i–VI–III–VII | Minor-key pop and rock | "Zombie" (The Cranberries) |
The same progression sounds remarkably different across genres because of tempo, instrumentation, melody, and feel. But the underlying harmonic skeleton is the same in every case, which is exactly what Roman numerals are designed to make visible.
Inversions and figured bass numbers
So far every Roman numeral has assumed the chord is in root position (the lowest note of the chord is the chord's root). When a chord is inverted, small numbers next to the Roman numeral indicate which note is in the bass.
The conventions come from figured bass, but the basics are simple:
- I or V alone means root position.
- I⁶ or V⁶ means first inversion (the third of the chord is in the bass).
- I⁶/₄ or V⁶/₄ means second inversion (the fifth of the chord is in the bass).
- V⁷ means a dominant seventh chord (V plus a minor seventh on top) in root position.
- V⁶/₅, V⁴/₃, V⁴/₂ are the inversions of V⁷.
You'll also occasionally see Roman numerals with a slash, like V/V (read "five of five"). This is a secondary dominant, a chord that acts as the V of another chord in the key. In C major, V/V would be D major (the V of G), which leads strongly to G (the V of C). Secondary dominants are how composers add chromatic color without leaving the key entirely.
Try this in Flat: write your first Roman numeral progression
The system clicks faster when you write it than when you read about it. This takes about five minutes.
Run this in Flat:
- Open a new score in C major. Write four whole notes in the bass clef: C, G, A, F. That's a I–V–vi–IV progression.
- Now write the same progression in G major: G, D, E, C. Notice that the chords are different absolute pitches, but the Roman numeral pattern (I–V–vi–IV) is identical.
- Transpose to A minor: A, F, E, D. That's a i–VI–v–iv. Same logic, different key and mode.
Three keys, one progression, three different sounds. That's the entire point of Roman numeral analysis in one short session.
Using Roman numerals in Flat
Flat includes a dedicated text-based input for adding Roman numerals to any score. Type the Roman numeral as you'd write it on paper (uppercase for major, lowercase for minor, plus any symbols), and Flat formats it correctly above the staff. The system also reads the Roman numerals from your score and displays them next to the input as you work.
The full how-to is documented in our Roman numerals help article.
Frequently asked questions about Roman numerals in music
What do Roman numerals mean in music?
They label chords by their position in a key, not their absolute pitch. The number is the scale degree (I, II, III, IV, V, VI, VII), the case indicates the chord quality (uppercase for major, lowercase for minor), and added symbols indicate diminished, augmented, or seventh chords.
Why are some Roman numerals uppercase and some lowercase?
Uppercase numerals (I, IV, V) represent major chords. Lowercase numerals (ii, iii, vi) represent minor chords. Lowercase with a small circle (vii°) represents a diminished chord. The case alone tells you the chord quality before you read anything else.
What are the Roman numerals for the C major scale?
I (C major), ii (D minor), iii (E minor), IV (F major), V (G major), vi (A minor), vii° (B diminished). The same case-and-quality pattern applies to every major key.
What are the Roman numerals for a minor key?
In natural minor: i (minor), ii° (diminished), III (major), iv (minor), v (minor), VI (major), VII (major). In real-world music, the v is often made major (V) by borrowing from the harmonic minor, especially in cadences.
What does V7 mean?
V7 is the dominant seventh chord. It's the V chord with a minor seventh added on top. In C major, V is G major (G, B, D), and V7 is G7 (G, B, D, F). V7 is one of the most common chords in Western music because of its strong pull back to I.
What does ii–V–I mean?
It's the most common chord progression in jazz, and one of the most common in all of tonal music. In C major: D minor (ii) → G major (V) → C major (I). Each chord moves down by a fifth, which creates a smooth voice-leading path back to the tonic.
What is a secondary dominant in Roman numeral notation?
A secondary dominant is written with a slash, like V/V ("five of five"). It's the dominant chord of another chord in the key. V/V in C major is D major (the V of G, which is the V of C). Secondary dominants add chromatic color without changing keys.
Are Roman numerals used in jazz?
Yes. Jazz uses Roman numerals heavily, especially for analyzing standards and teaching chord substitutions. The ii–V–I progression is the foundational unit of jazz harmony, and most jazz education leans on Roman numeral analysis to make patterns visible across keys.
Key takeaways
Roman numerals are the universal language for chords in tonal music. They let you describe a chord progression without committing to a key, recognize the same patterns across songs in different keys, and analyze music in a way that makes the underlying logic visible. Once you have the major and minor patterns memorized, and a handful of common progressions in your ear, you can read most of popular and classical music's chord vocabulary at a glance.
The best way to internalize the system is to start using it. Open Flat, write a short progression in one key, label each chord with its Roman numeral, then transpose to a new key and watch the numerals stay the same while the actual chords change.