Roman Numeral Analysis

The universal language musicians use to describe chords and progressions in any key.

What is Roman numeral analysis?

Roman numeral analysis is a system for labeling chords based on the scale degree of their root note. Instead of saying “C major chord, then F major chord, then G major chord,” a musician writes I – IV – V. The numerals describe the function of each chord — its relationship to the key — rather than its absolute pitch. This makes it possible to discuss chord progressions that work in every key using a single set of labels.

The system dates back to the late 18th century and remains the standard analytical tool in classical theory, jazz harmony, and pop songwriting alike. If you can read Roman numerals, you can transpose any progression to any key instantly, communicate with other musicians without specifying a key, and recognize familiar harmonic patterns across thousands of songs.

Why it matters

When someone says “this song uses a I – vi – IV – V,” every musician in the room knows the sound — regardless of whether the song is in C, G, or E♭. Roman numerals are the harmonic equivalent of solfège: a key-independent shorthand that makes patterns visible.

The numbering system

Each scale degree gets a Roman numeral from I to VII. The case of the numeral tells you the chord quality, and additional symbols refine it further.

Symbol	Quality	Example in C
I	Major triad	C (C – E – G)
ii	Minor triad	Dm (D – F – A)
iii	Minor triad	Em (E – G – B)
IV	Major triad	F (F – A – C)
V	Major triad	G (G – B – D)
vi	Minor triad	Am (A – C – E)
vii°	Diminished triad	B° (B – D – F)
V⁷	Dominant seventh	G7 (G – B – D – F)
III+	Augmented triad	E+ (E – G♯ – B♯)

Rule of thumb

Uppercase = major or augmented. Lowercase = minor or diminished. The ° symbol means diminished; the + symbol means augmented. A superscript 7 adds a seventh to the chord.

Roman numerals in major keys

When you build a triad on each degree of the major scale using only notes from that scale, you get a fixed pattern of chord qualities. This pattern is the same in every major key — it’s one of the most important facts in tonal harmony.

Degree	Numeral	Quality	Function	C major
1st	I	Major	Tonic	C
2nd	ii	Minor	Supertonic	Dm
3rd	iii	Minor	Mediant	Em
4th	IV	Major	Subdominant	F
5th	V	Major	Dominant	G
6th	vi	Minor	Submediant	Am
7th	vii°	Diminished	Leading tone	B°

Notice the pattern: three major chords (I, IV, V), three minor chords (ii, iii, vi), and one diminished chord (vii°). This pattern holds in every major key — in G major, I is G, ii is Am, iii is Bm, IV is C, V is D, vi is Em, and vii° is F♯°.

Roman numerals in minor keys

Minor keys are more complex because there are three minor scale variants (natural, harmonic, and melodic), and composers mix chords from all three freely. The natural minor gives the “default” diatonic set, but the raised 7th degree from the harmonic minor is so common that V (major) and vii° are standard in minor-key analysis.

Degree	Natural	Harmonic	A minor
1st	i	i	Am
2nd	ii°	ii°	B°
3rd	III	III+	C / C+
4th	iv	iv	Dm
5th	v	V	Em / E
6th	VI	VI	F
7th	VII	vii°	G / G♯°

Practical tip

In most real music, minor keys use the harmonic minor’s V (major) and vii° rather than the natural minor’s v (minor) and VII (major). When you see “V – i” in a minor key, the V chord contains the raised 7th degree — that leading tone is what gives the resolution its pull.

Figured bass and inversions

Roman numerals can include small numbers (called figures) to indicate chord inversions. The figures describe the intervals above the bass note. In practice, most musicians memorize the shorthand rather than calculating intervals each time.

Position	Triad figure	7th chord figure	Meaning
Root position	(no figure) or ⁵₃	⁷	Root is in the bass
First inversion	⁶ or ⁶₃	⁶₅	3rd is in the bass
Second inversion	⁶₄	⁴₃	5th is in the bass
Third inversion	—	⁴₂ or ²	7th is in the bass

For example, I⁶ means a tonic triad in first inversion (the 3rd is in the bass), and V⁶₅ means a dominant seventh chord in first inversion (the 3rd of V is in the bass, with a 6th and 5th above it).

Secondary dominants

A secondary dominant is a chord that acts as the V (dominant) of a chord other than the tonic. It’s written with a slash: V/V means “the dominant of the dominant.” Secondary dominants borrow a note from outside the key to create a temporary leading tone, adding color and momentum to a progression.

Symbol	Reads as	In C major	Resolves to
V/V	Five of five	D major (D – F♯ – A)	V (G)
V/ii	Five of two	A major (A – C♯ – E)	ii (Dm)
V/iii	Five of three	B major (B – D♯ – F♯)	iii (Em)
V/IV	Five of four	C major (C – E – G)	IV (F)
V/vi	Five of six	E major (E – G♯ – B)	vi (Am)
V⁷/V	Five-seven of five	D7 (D – F♯ – A – C)	V (G)

How to spot them

If you see a major chord or dominant seventh chord that doesn’t belong to the key, check whether it resolves up a fourth (or down a fifth) to a diatonic chord. If it does, it’s almost certainly a secondary dominant. The “V/” label names the resolution target.

Common chord progressions

Thousands of songs share a handful of core harmonic patterns. Here are the progressions every pianist should recognize by numeral and by ear.

I – IV – V – IThe foundational cadential pattern

In C: C – F – G – C

The backbone of Western tonal music. Tonic establishes the key, subdominant creates motion, dominant builds tension, and the return to tonic resolves it.

I – V – vi – IVThe "four-chord song"

In C: C – G – Am – F

One of the most common pop progressions of the past 30 years. Used in countless hits across genres — recognizable by its optimistic-to-bittersweet emotional arc.

ii – V – IThe jazz turnaround

In C: Dm – G – C

The essential jazz progression. The ii chord sets up the dominant, the V creates tension, and the I resolves. Extended to ii⁷ – V⁷ – Iᐞ⁷ with seventh chords in jazz practice.

I – vi – IV – VThe "50s progression"

In C: C – Am – F – G

The doo-wop classic. Provides a complete harmonic loop that cycles smoothly, making it ideal for repeated verse structures.

vi – IV – I – VThe "sensitive" progression

In C: Am – F – C – G

Starting on the vi gives a minor-key flavor even though the key is major. Creates an emotional, reflective quality heard across rock, pop, and indie music.

I – IV – vi – VPop ballad staple

In C: C – F – Am – G

A versatile loop that moves from brightness (I–IV) through melancholy (vi) to expectation (V), cycling naturally back to I.

i – iv – V – iMinor cadential pattern

In C: Am – Dm – E – Am (in A minor)

The minor-key equivalent of I–IV–V–I. The V chord uses the harmonic minor's raised 7th (G♯ in A minor) for a strong resolution to the tonic.

How to analyze a chord progression

Follow these steps when you encounter a new piece and want to label its chords with Roman numerals.

Identify the key

Look at the key signature and the final chord. The key signature tells you which major or minor key you're most likely in; the final chord usually confirms the tonic.

Spell out the diatonic chords

Write the seven diatonic triads (and sevenths, if relevant) for that key. This gives you a reference grid: I, ii, iii, IV, V, vi, vii° for major; i, ii°, III, iv, V, VI, vii° for minor.

Label each chord

Match each chord in the piece to its Roman numeral. Check the root, quality (major/minor/diminished), and bass note (for inversions).

Flag chromatic chords

Any chord that doesn't fit the diatonic set is chromatic — likely a secondary dominant (V/x), a borrowed chord (from the parallel key), or an applied chord. Label it with its function.

Look for patterns

Step back and identify familiar sequences: cadences (V–I, IV–I, V–vi), common loops (I–vi–IV–V), circle-of-fifths motion (vi–ii–V–I), or sequence patterns.

Annotate phrase structure

Mark where phrases begin and end. Each phrase typically ends with a cadence. The cadence type tells you whether the phrase is a question (half cadence) or an answer (authentic cadence).

Frequently asked questions

Why use Roman numerals instead of chord names?

Chord names (C, G7, Am) are key-specific — they only describe one key at a time. Roman numerals describe function: "V" means "the dominant" in any key. This lets you discuss, compare, and transpose progressions without rewriting every chord name. A ii–V–I is the same pattern whether you're playing in C, F♯, or B♭.

What does the case (upper vs lower) tell me?

Uppercase numerals (I, IV, V) indicate major chords. Lowercase numerals (ii, iii, vi) indicate minor chords. A lowercase numeral with a degree symbol (vii°) indicates diminished. An uppercase numeral with a plus sign (III+) indicates augmented.

What is a secondary dominant?

A secondary dominant is a chord that temporarily acts as the V (dominant) of a diatonic chord other than the tonic. For example, V/V in C major is D major — it's the dominant of G (the dominant). The notation always tells you the target: V/vi means "the dominant of vi," which in C major is E major resolving to Am.

How do Roman numerals work in minor keys?

In minor keys, the diatonic triads are i, ii°, III, iv, v, VI, VII (natural minor). However, most music raises the 7th degree (harmonic minor), which changes v to V (major) and VII to vii° (diminished). Analyses often mix chords from the natural, harmonic, and melodic minor scales.

What do the small numbers (figures) mean?

The figures indicate inversions. For triads: no figure = root position, ⁶ = first inversion, ⁶₄ = second inversion. For seventh chords: ⁷ = root position, ⁶₅ = first inversion, ⁴₃ = second inversion, ⁴₂ = third inversion. They describe which chord tone is in the bass voice.

Is Roman numeral analysis used in jazz?

Absolutely. Jazz musicians use Roman numerals constantly — the ii–V–I is the most fundamental jazz progression. Jazz analysis adds extensions (ii⁷–V⁷–Iᐞ⁷) and substitutions (tritone sub: ♭II⁷ for V⁷). Nashville number charts use Arabic numerals (1, 4, 5) for the same purpose — they're Roman numerals in disguise.