How do Roman numerals work?

Roman numerals use seven letters: I (1), V (5), X (10), L (50), C (100), D (500), M (1000). Numbers are formed by combining these symbols. Normally, symbols are arranged from largest to smallest (XVI = 16). When a smaller symbol precedes a larger one, it's subtracted (IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900).

What are the rules for writing Roman numerals?

Only I, X, and C can be subtracted. A symbol can be repeated up to three times (III = 3, XXX = 30). Subtraction is only allowed for one symbol before a larger one (IV is valid, IIV is not). The same symbol in subtraction position can't repeat (IIX is invalid, use VIII for 8). Standard Roman numerals only go up to 3999 (MMMCMXCIX).

Are Roman numerals still used today?

Yes, Roman numerals are used for clock faces, book chapters, movie copyright dates, Super Bowl numbering, outline formatting, and building cornerstones. They're also used for royal names (Elizabeth II) and in formal contexts. However, they're impractical for arithmetic, which is why Arabic numerals (0-9) replaced them for calculations.

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Unit ConversionsVerifiedFeb 2026

Roman Numeral Converter

Name: Roman Numeral Converter
Author: Biggest Calculator Hub

Convert between Roman numerals (I, V, X, L, C, D, M) and Arabic numbers (1-3999). Bidirectional converter with validation for historical and modern applications.

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How to Use the Roman Numeral Converter

This free roman numeral converter helps you quickly calculate result. Simply enter your values in the fields above and click "Calculate" to see your results instantly.

Understanding Your Results

After entering your information, the calculator will display your results including result, breakdown. Each result is calculated using standard formulas used by financial professionals and experts in the field.

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