Decimal to Roman Numeral Converter

Convert decimal numbers to Roman numerals. Perfect for classical numbering, document formatting, and historical references.

Input (Decimal)
Enter a decimal number
Output (Roman)
Roman numeral representation

What is Decimal to Roman Numeral Conversion?

Decimal to Roman numeral conversion transforms modern Arabic numerals (0-9) into the ancient Roman numeral system using letters I, V, X, L, C, D, and M.

Roman Numeral System

Roman numerals use combinations of seven letters:

Basic Symbols:

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

Rules and Patterns

Addition Rule:

When a smaller numeral follows a larger one, add the values:

  • VI = 5 + 1 = 6
  • XV = 10 + 5 = 15

Subtraction Rule:

When a smaller numeral precedes a larger one, subtract:

  • IV = 5 - 1 = 4
  • IX = 10 - 1 = 9
  • XL = 50 - 10 = 40

Common Use Cases:

  • Clock faces and watches
  • Book chapters and volumes
  • Movie credits and copyright years
  • Building cornerstones and monuments
  • Outline numbering in documents

Examples:

  • 2024 = MMXXIV
  • 1999 = MCMXCIX
  • 444 = CDXLIV
  • 90 = XC