Roman Numeral Converter

Convert any number to Roman numerals and Roman numerals back to numbers. Includes a complete Roman numeral chart and rules explained.

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Roman Numeral Converter

Roman Numeral Chart

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

Comprehensive Guide & Practice

Master the mathematical principles, formulas, and step-by-step methods with worked examples and FAQs.

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1. Roman Numerals: Complete Guide

Roman numerals are a numeral system originating in ancient Rome that used letters from the Latin alphabet to represent numbers. They were the standard writing system for numbers throughout Europe well into the Late Middle Ages.

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2. The Seven Roman Numeral Symbols

There are seven base symbols: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1,000.

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3. Subtractive Notation

Roman numerals use a subtractive rule: when a smaller symbol precedes a larger one, you subtract the smaller from the larger:

  • IV = 4 (5 − 1)
  • IX = 9 (10 − 1)
  • XL = 40 (50 − 10)
  • XC = 90 (100 − 10)
  • CD = 400 (500 − 100)
  • CM = 900 (1000 − 100)
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4. Common Roman Numerals

  • XI = 11 | XIV = 14 | XIX = 19 | XXI = 21 | XLII = 42 | L = 50
  • LXVIII = 68 | XCIX = 99 | C = 100 | CCXLVII = 247 | D = 500
  • DCCC = 800 | CM = 900 | M = 1000 | MCMXCIX = 1999 | MMXXVI = 2026

See also: Number Base Converter | Roman Numerals Full Guide | Number Systems Guide