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Roman Numeral Converter

Convert between Roman numerals and Arabic numbers instantly. Free online Roman numeral converter.

swap_horizConvert Roman / Arabic

Supports numbers 1-3,999,999. Use underscore for overline (e.g., _X = 10,000)

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Basic Symbols (1-1000)

Vinculum/Overline (x1000)

help_outlineUsing Vinculum (Overline)

For numbers larger than 3,999, Romans used a vinculum (overline) to multiply by 1,000.

Input format: Use underscore before a letter to indicate an overline.

_X = X with overline = 10,000
_XMCMLIV = 11,954
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How to Use

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  1. Enter an Arabic number (1-3999) to convert to Roman numerals
  2. Or enter a Roman numeral to convert to an Arabic number
  3. Click the appropriate convert button
  4. View the result and conversion explanation
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What is Roman Numeral Converter?

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Roman numerals are a numeral system that originated in ancient Rome. They use letters from the Latin alphabet (I, V, X, L, C, D, M) to represent values. Roman numerals are still used today for clock faces, book chapters, movie sequels, and formal documents.

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Formula

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Roman Numeral Values:

I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000

Subtractive Notation:

IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900

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Examples

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  • 2024 = MMXXIV (M+M+X+X+IV)
  • 1999 = MCMXCIX (M+CM+XC+IX)
  • 49 = XLIX (XL+IX)
  • 444 = CDXLIV (CD+XL+IV)
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FAQ

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Why do Roman numerals only go up to 3999?expand_more
The standard Roman numeral system can only represent numbers up to 3999 (MMMCMXCIX). Larger numbers historically used different notations like a bar over the numeral (meaning ×1000) or special symbols.
What is subtractive notation?expand_more
Subtractive notation places a smaller value before a larger one to indicate subtraction. For example, IV means 5-1=4, and IX means 10-1=9. This makes numerals shorter and easier to read.
Are Roman numerals still used today?expand_more
Yes! Roman numerals appear on clock faces, in movie titles (sequels), book chapters, Super Bowl numbers, building cornerstones, and formal outlines.