Paste a progression — get Roman numerals.
Type chords (e.g. C Am F G) and pick a key — we'll convert them to Roman numerals so you can transpose, analyse, or learn the function of each chord.
Try an example:
Analysis in C major
I
C
C
vi
A
Am
IV
F
F
V
G
G
I, IV, VMajor triad
ii, iii, viMinor triad
vii°Diminished triad
⁷Dominant 7th (e.g. V⁷)
ᴹ⁷Major 7th (e.g. Iᴹ⁷)
♭II, ♭VI, ♭VIIBorrowed / chromatic chords
What is Roman numeral analysis?
Roman numerals describe the function of each chord in a key — the “I” (one) is home, the “V” (five) creates tension, the “vi” (six) is the relative minor. Uppercase = major, lowercase = minor, ° = diminished.
Why songwriters use it
Because it's key-independent. I–V–vi–IV in C is C–G–Am–F; in G it's G–D–Em–C. Same emotional shape, different notes. Once you spot the pattern in one song, you can transpose it to any key instantly.