Roman Numeral Converter
Convert between Roman numerals and Arabic numbers instantly.
Arabic Number
Roman Numeral
Quick examples
Roman numeral symbols
| Symbol | Value | Symbol | Value |
|---|---|---|---|
| I | 1 | V | 5 |
| X | 10 | L | 50 |
| C | 100 | D | 500 |
| M | 1000 | — | — |
Subtractive pairs
IV= 4IX= 9XL= 40XC= 90CD= 400CM= 900
A smaller symbol placed before a larger one means subtraction (e.g. IV = 5 − 1 = 4).
Convert any Arabic number (1–3999) to Roman numerals and vice versa. Includes a subtractive notation reference, quick examples, and bidirectional input.
Key Features
Bidirectional
Type an Arabic number to get Roman numerals, or type Roman numerals to get the Arabic value — both inputs are live.
Validation
Invalid Roman numeral strings are detected and flagged with an error message.
Quick Examples
One-click buttons for common values: current year, year 2000, Super Bowl, Olympics, historical dates.
Symbol Reference
Built-in table of all 7 Roman numeral symbols and all 6 subtractive pairs (IV, IX, XL, XC, CD, CM).
How to Use
- 1Type a number from 1 to 3999 in the Arabic field to see its Roman numeral form.
- 2Or type Roman numeral letters (e.g. MMXXVI) to convert back to Arabic.
- 3Use the quick example buttons for commonly searched values.