Roman Numerals Converter

Convert between Roman numerals and Arabic numbers. Enter a number or Roman numeral to convert.

This tool generates fictitious data intended exclusively for software testing and development purposes. The data does not correspond to real people or entities and must not be used for illegal, fraudulent purposes, or in ways that violate the privacy of others. Compliant with LGPD (Brazilian Data Protection Law).

See also:

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Codice Fiscale (Italy)
Fictitious Data in Testing
URL Encode/Decode

About Roman Numerals Converter

What are Roman numerals?

Roman numerals are a numeral system originating from ancient Rome that uses combinations of letters to represent values: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000). Numbers are formed by adding values (VI = 6) or using subtractive notation for 4s and 9s (IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900). The standard system represents numbers from 1 to 3999.

How does the converter work?

Enter a decimal number (1-3999) to convert it to Roman numerals, or enter a Roman numeral to convert it to decimal. The converter validates input in both directions, ensuring correct subtractive notation and rejecting invalid sequences. It handles all standard Roman numeral rules including proper ordering of values and correct use of subtractive pairs.

Where are Roman numerals used today?

Roman numerals remain widely used in clock faces, book chapter numbering, movie sequel titles, Super Bowl numbering, copyright year notices, outline formatting, and academic citations. In programming, developers encounter them in data formatting requirements, content management systems that use Roman numeral lists, and coding challenges. Understanding the conversion algorithm is a classic computer science exercise.