Roman Numeral Converter

Both directions, strict validation. Range: 1 to 3,999 (MMMCMXCIX).

Result

Roman numeral

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The symbols

  • I = 1, V = 5, X = 10
  • L = 50, C = 100
  • D = 500, M = 1,000

Subtractive notation

Up to three identical symbols in a row (III = 3, XXX = 30). For 4 and 9, put a smaller letter before a larger one — that's subtractive: IV = 5−1 = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900. So 1994 is M (1000) + CM (900) + XC (90) + IV (4) = MCMXCIV.

Why no zero?

The Roman numeral system, derived from etrusan tally marks, never developed a symbol for zero — they used nullus (nothing) when they needed to express it. The concept of zero as a digit came to Europe via Indian and Arabic mathematics around the 12th century, but by then Roman numerals were already being replaced by Arabic numerals for arithmetic.