Roman Numerals
Convert numbers to and from Roman numerals (1–3999).
Convert
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How it works
How it works
- Number → Roman: greedy subtraction using pairs like CM (900), CD (400), XC (90), XL (40), IX (9), IV (4).
- Roman → Number: scan from right to left; subtract when a smaller symbol precedes a larger one.
- Validation uses a regex for standard forms up to 3999 (no overlines for 5000+).
Privacy & Security
All local.
Accuracy, Limits & Tips
Supports only standard forms up to 3999.
Examples
- 1999 → MCMXCIX
- MMXXV → 2025
Looking for broader guides and best practices? Visit the ToolsAreUs Blog for indexes (like the full tool list) and articles (e.g. secure password generation).