Roman Numeral Analyzer
Play or enter notes
| 1 | Note |
| 2 | Interval |
| 3+ | Chord |
| 5+ | Scale or mode |
Diatonic triads by degree
| Degree | Major key | Natural minor key |
|---|---|---|
| 1 | I | i |
| 2 | ii | ii diminished |
| 3 | iii | III |
| 4 | IV | iv |
| 5 | V | v |
| 6 | vi | VI |
| 7 | vii diminished | VII |
The harmonic minor raises the seventh degree, which turns v into V and VII into vii diminished. That is the usual reason a minor key shows a major dominant.
What each function does
| Function | Usual numerals | Role in the phrase |
|---|---|---|
| Tonic | I, vi, iii | Rest. The phrase has arrived. |
| Predominant | ii, IV | Approach. Leads toward the dominant. |
| Dominant | V, vii diminished | Tension. Pulls back to the tonic. |
Reference
Why is there no numeral until I choose a key?
Because a Roman numeral is a statement about a key, not about a chord. G major is V in C, I in G, and IV in D, and nothing about the three notes themselves decides which. With the key on Auto the tool says how many keys contain the chord and leaves the choice to you; pick one and the numeral and its function appear immediately.
What do uppercase and lowercase numerals mean?
Case carries the quality of the triad. Uppercase is major, lowercase is minor, a lowercase numeral with a small circle is diminished, and an uppercase numeral with a plus sign is augmented. So in a major key the seven diatonic triads read I, ii, iii, IV, V, vi and vii diminished, and the case alone tells you the third of each.
What is harmonic function?
A grouping of the degrees by what they tend to do. Tonic chords are where a phrase rests, predominant chords lead toward the dominant, and dominant chords pull back to the tonic. It is the layer above the numeral: two different numerals can share one function, which is why a substitution often works even though the chord changed.
Does it handle sevenths, inversions and borrowed chords?
Sevenths and inversions yes: the numeral follows the chord the analysis identified, and the Chord tab states the bass and the inversion separately. A chord from outside the key is reported honestly rather than forced into a numeral, since the point of the numeral is that it describes a degree of the scale you selected.
To see the numeral in every key at once instead of one, use the Key Finder. To name what a run of numerals adds up to, use the Cadence Finder.