Roman Numeral Converter

Professional Roman numeral converter supporting bidirectional conversion between Roman and Arabic numerals with real-time conversion, step breakdown and one-click copy

Roman Numeral Converter

Enter Arabic number or Roman numeral

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Result

Roman Numeral Rules

Basic Symbols

Roman numerals use the following symbols:

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

Composition Rules

Repeat the same symbol:III = 3(max 3 in a row)
Smaller on the right of larger:VI = 6(addition)
Smaller on the left of larger:IV = 4(subtraction)
Subtraction only for:IV(4), IX(9), XL(40), XC(90), CD(400), CM(900)

Common Examples

Arabic number	Roman numeral
1	I
4	IV
9	IX
40	XL
90	XC
400	CD
900	CM
1999	MCMXCIX