Roman Numeral Converter
? Frequently Asked Questions
How do Roman numerals work?
Roman numerals use letters: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. Letters are combined additively (VI=6) or subtractively (IV=4). The largest standard number is 3999 (MMMCMXCIX).
Can I convert from Roman to decimal and back?
Yes, the converter works bi-directionally. Enter Roman numerals (like XIV) to get 14, or enter 14 to get XIV. It validates Roman numeral syntax and converts accurately.
What's the subtractive notation rule?
Smaller values before larger ones are subtracted: IV=4 (5-1), IX=9 (10-1), XL=40, XC=90, CD=400, CM=900. Only I, X, and C can be subtracted, and only from the next two larger values.
How high can Roman numerals go?
Standard Roman numerals go to 3999. For larger numbers, a vinculum (overline) multiplies by 1000, so V̅ = 5000. Some systems use parentheses or other notation for even larger values.
Why don't Roman numerals have zero?
Ancient Romans didn't use zero as a number concept. Roman numerals are additive, representing counts rather than place-value positions. Zero was introduced to European mathematics later from Arabic numerals.
Is my data safe and secure?
Yes, absolutely! This tool runs entirely in your browser. All data processing happens locally on your device - nothing is uploaded to our servers. Your files and data never leave your computer, ensuring complete privacy and security.