Roman Numeral Converter

Convert Roman numerals and Arabic numbers in both directions, and validate canonical Roman notation from 1 to 3999.

Roman Numeral Converter

Convert Roman numerals and Arabic numbers online in both directions, with strict validation for the standard `1 - 3999` Roman numeral range.

How to use

  1. Enter an Arabic number to get its canonical Roman numeral.
  2. Or enter a Roman numeral to decode it back into an integer and validate the notation.
  3. Review the normalized output and symbol breakdown to understand the numeral structure.
  4. Copy the result for chapters, lists, titles, historical pages, or data cleanup work.

Features

  • Bidirectional Roman numeral ↔ Arabic number conversion
  • Uppercases, trims spaces, and validates canonical Roman notation
  • Includes the `1 - 3999` range, normalized output, and symbol breakdown

Why use this?

  • Useful for book chapters, outlines, sequels, historical references, and learning materials
  • Faster than manual lookup tables and better at catching non-canonical forms like `IIII` or `IC`
  • Runs instantly in the browser with local conversion, validation, and copy support

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