Roman Numeral Converter
Convert chord progressions into music theory Roman numeral notation (and vice versa) across any key and scale mode. Includes visualizers for piano and guitar, Web Audio preview, and classic integer-to-Roman conversion.
Conversion Breakdown (4 Chords)
Active chord note positions across 2 octaves:
Export & Sharing Options
Download a standard MIDI file (.mid) with VLQ delta encoding to drag into Ableton, Logic, FL Studio, or Pro Tools.
Convert Chords and Roman Numerals in Any Key
A Roman Numeral Converter helps you translate chord progressions into music theory Roman numeral notation and convert Roman numerals back into chord names for virtually any key and supported scale mode. Whether you’re studying harmony, analyzing songs, writing chord progressions, or transposing music, the converter makes it easy to understand how chords function within a key. It also includes a classic integer-to-Roman numeral converter, interactive piano and guitar visualizers, Web Audio playback, and MIDI export.
Instead of manually calculating scale degrees and harmonic functions, you can enter either chord symbols or Roman numerals and receive an accurate conversion in seconds.
How to Use the Roman Numeral Converter
Using the converter is simple:
- Select the conversion mode, such as Chord → Roman Numerals, Roman Numerals → Chords, or Classic Integer.
- Choose the key root and scale mode when working with chord progressions.
- Enter your chords or Roman numeral notation into the input box.
- Click Convert Notation to generate the results.
- Review the converted progression, harmonic breakdown, and chord functions.
- Preview the progression using the built-in audio player.
- Export the converted progression as a Standard MIDI (.mid) file if needed.
The converter accepts common chord symbols like C, Dm7, G7, Cmaj7, as well as Roman numeral notation including I, ii7, V7, Imaj7, bVI, and V7/vi.
If you already have a chord progression and want a deeper harmonic breakdown, the Chord Progression Analyzer provides detailed key detection, cadence analysis, and harmonic functions.
Convert Between Chords and Roman Numerals
Roman numerals describe the function of chords within a musical key rather than their letter names.
For example:
| Chords | Roman Numerals |
|---|---|
| C – G – Am – F | I – V – vi – IV |
| G – D – Em – C | I – V – vi – IV (in G Major) |
Because Roman numerals represent harmonic relationships, the same progression can be recognized even after changing keys.
The converter also supports more advanced harmonic notation, including:
- Secondary dominants
- Borrowed chords
- Modal interchange
- Seventh chords
- Extended chord symbols
If you’re creating a progression from scratch before converting it, the Chord Progression Calculator is a helpful companion tool.
Classic Integer to Roman Numeral Conversion
In addition to music theory notation, the tool includes a traditional Roman numeral converter for whole numbers.
Enter any integer from 1 to 3999, and the converter generates the corresponding Roman numeral representation.
For example:
| Number | Roman Numeral |
|---|---|
| 4 | IV |
| 27 | XXVII |
| 399 | CCCXCIX |
| 2026 | MMXXVI |
This feature is useful for educational purposes, numbering systems, outlines, historical references, and other situations where classic Roman numerals are required.
Preview Chords and Visualize the Results
When converting chord progressions, the tool provides more than text output.
It includes an interactive two-octave piano keyboard and a standard six-string guitar fretboard that display the converted chord voicings in real time.
The built-in Web Audio player lets you hear the progression using multiple instrument sounds while adjusting playback speed and looping the sequence.
When you’re finished, export the converted progression as a Standard MIDI (.mid) file for use in compatible digital audio workstations.
If you’re preparing the progression for piano performance, the Piano Chord Progression Generator can generate playable piano voicings automatically.
Tips for Working with Roman Numerals
Roman numeral notation becomes much easier to understand with regular practice.
- Select the correct key before converting chord progressions.
- Remember that uppercase numerals generally represent major chords, while lowercase numerals represent minor chords.
- Use Roman numerals to compare songs written in different keys.
- Experiment with different musical modes to observe changing harmonic functions.
- Preview the converted progression to connect notation with sound.
- Export MIDI versions when comparing different harmonic ideas.
For a deeper understanding of harmony, explore What Is a Chord Progression?, Roman Numeral Chords, How to Write Chord Progressions, and Common Chord Progressions to see how Roman numeral notation is used in real songs.
Frequently Asked Questions
What is a Roman numeral converter?
A Roman numeral converter translates chord progressions into music theory Roman numeral notation, converts Roman numerals back into chord names, and can also convert whole numbers into classic Roman numerals.
Can I convert Roman numerals back into chords?
Yes. The converter works in both directions, allowing you to convert chord names into Roman numerals or Roman numeral notation back into chords using the selected key and scale mode.
Does the converter support advanced harmonic notation?
Yes. It supports secondary dominants, borrowed chords, modal interchange, seventh chords, and other common harmonic extensions used in music theory.
Can I convert regular numbers into Roman numerals?
Yes. The classic converter supports integers from 1 to 3999, making it useful for both music theory and traditional Roman numeral notation.
Can I export converted progressions as MIDI files?
Yes. Converted chord progressions can be exported as Standard MIDI (.mid) files directly from your browser for use in compatible digital audio workstations.