Roman Numeral Converter

Convert between Arabic numbers (1-3999) and Roman numerals.

Arabic Number

Roman Numeral

Reference

I

1

IV

4

V

5

IX

9

X

10

XL

40

L

50

XC

90

C

100

CD

400

D

500

CM

900

M

1000

Rules

I before V or X subtracts 1 (IV = 4, IX = 9)
X before L or C subtracts 10 (XL = 40, XC = 90)
C before D or M subtracts 100 (CD = 400, CM = 900)
Symbols cannot be repeated more than 3 times
Valid range: 1-3999