About this tool
This free Roman numeral converter turns numbers into Roman numerals and Roman numerals back into numbers — both directions, updating as you type. It uses standard notation (I, V, X, L, C, D, M) and validates the result, so it rejects incorrect forms like IIII.
Everything runs in your browser — nothing is uploaded.
Features
- Two-way — number ⇄ Roman numeral
- Live conversion as you type
- Standard notation for 1 to 3999
- Rejects invalid Roman numerals
Common uses
- Write a year (like a birth year or copyright date) in Roman numerals
- Decode Roman numerals on clocks, films and monuments
- Homework and history help
How to use it
- Type a number (1–3999) to see its Roman numeral
- Or type a Roman numeral to get the number
- Read the result in the other field instantly
