Roman Numeral Converter
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Convert any number to Roman numerals or any Roman numeral back to a number.
Enter your values below and click Calculate for instant results.
Roman numerals use combinations of seven letters to represent numbers: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000). Numbers are formed by combining these symbols, generally from largest to smallest from left to right. When a smaller value appears before a larger value, it is subtracted rather than added.
The subtractive rule: IV = 4 (not IIII), IX = 9 (not VIIII), XL = 40, XC = 90, CD = 400, CM = 900. Only specific combinations are valid: I can precede V and X, X can precede L and C, and C can precede D and M. Other combinations like IL (49) are non-standard.
Roman numerals appear on clock and watch faces, in movie copyright years and sequel numbering (Rocky IV, Super Bowl LVIII), for chapter and section numbering in books and legal documents, on building cornerstones and monuments, for naming kings and popes (King Charles III), and in the numbering of Olympic games and World Cups.
The standard Roman numeral system does not have a symbol for zero and cannot represent fractions or negative numbers. The system becomes unwieldy for large numbers because it only has single symbols up to 1000 (M). This calculator handles numbers from 1 to 3999, the practical range of the classic system.