Roman Numeral Converter
Type a number to get its Roman numeral, or type a Roman numeral to get its number — both directions update instantly, right in your browser.
Number → Roman
Enter a number to convert.
Roman → Number
Enter a Roman numeral to convert.
What's the valid range?
1 to 3999. Roman numerals have no symbol for zero or negative numbers, and the classical system runs out of letters above 3999 (M is the largest symbol, at 1000).
Why does the tool reject numerals like "IIII" or "IC"?
Those aren't canonical Roman numerals — 4 is written "IV" and 96 is "XCVI", never with four repeated symbols or a subtraction skipping a tier. This tool only accepts the standard spelling, so a rejected numeral usually means a typo.
Is anything sent to a server?
No. The conversion runs entirely in your browser with JavaScript — nothing is uploaded.