Roman Numeral ↔ Arabic Number
Convert between Roman numerals and Arabic numbers. Convert the numerical system used in ancient Rome to modern numbers or vice versa.
Supports range 1-3999
Real-time bidirectional conversion
Learn historical number system
Arabic → Roman
Convert Arabic numbers to Roman numerals.
Basic Roman Numeral Rules
Basic Numbers
I = 1
V = 5
X = 10
L = 50
C = 100
D = 500
M = 1000
Combination Rules
- • Repeat same character: III = 3
- • Smaller before larger: IV = 4, IX = 9
- • Larger before smaller: VI = 6, XI = 11
- • Maximum 3 repetitions allowed
Special Combinations
IV = 4
IX = 9
XL = 40
XC = 90
CD = 400
CM = 900
Conversion Examples
2024MMXXIV
1994MCMXCIV
444CDXLIV
99XCIX
27XXVII