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SeniorTools

Free Online Roman Numeral Converter

Convert any whole number from 1 to 3999 into its Roman numeral equivalent, or convert a Roman numeral string back to an Arabic number. Invalid numerals are detected and rejected.

Arabic Number (1 – 3999)
Roman Numeral

Roman Numeral Symbol Reference

SymbolValue
I1
V5
X10
L50
C100
D500
M1000

Subtractive notation: placing a smaller symbol before a larger one means subtraction — IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900.