Roman Numeral Converter

Convert any number from 1 to 3,999,999 to Roman numerals, or decode any Roman numeral back to an Arabic number. Includes a step-by-step breakdown showing how each part is composed.

Roman Numeral Symbols

I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000. For numbers above 3999, the tool uses the vinculum (overline) notation: M̅ = 1,000,000, D̅ = 500,000, C̅ = 100,000, etc.

Conversion Rules

Roman numerals are written from largest to smallest value. Subtraction notation is used for 4 (IV), 9 (IX), 40 (XL), 90 (XC), 400 (CD), 900 (CM). The same symbol is never repeated more than three times in a row.

Step-by-Step Breakdown

The converter shows exactly how each number is built. For example: 1999 = M (1000) + CM (900) + XC (90) + IX (9) = MCMXCIX. This helps understand the conversion logic.

Common Uses

Year conversions: 2024 = MMXXIV, 1999 = MCMXCIX, 1776 = MDCCLXXVI. Movie copyright dates, book chapters, clock faces, and Super Bowl numbering. Historical documents and royal titles.