Roman Numeral Converter
Convert between Arabic numbers (1-3999) and Roman numerals instantly. Free online bidirectional converter with validation, examples, and conversion history for ancient numeral system.
123CXXIIINumber to Roman
MCMXC1990Roman to Number
Quick Actions
Roman Numerals
Basic Symbols:
I1
V5
X10
L50
C100
D500
M1000
Subtraction Rules:
IV4 (5-1)
IX9 (10-1)
XL40 (50-10)
XC90 (100-10)
CD400 (500-100)
CM900 (1000-100)
Rules & Examples
Conversion Rules:
- Symbols are written from largest to smallest
- Maximum 3 consecutive identical symbols
- Only I, X, C can be subtracted
- Range: 1 to 3999
Common Examples:
XIV14
LXVI66
CDXLIV444
MMXXI2021
MMMCMXCIX3999