Roman Numeral Converter
Convert numbers to Roman numerals and back, with checks for correctly written numerals.
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How to use
- Type a number from 1 to 3,999 to see it in Roman numerals.
- Or type a Roman numeral to see its value.
- Copy either result with its copy button.
How it works
Standard Roman numerals use subtraction for 4s and 9s (IV, IX, XL, XC, CD, CM) and never repeat a symbol more than three times. The checker rejects non-standard forms such as IIII or VX so you can trust the result.
Limitations
- Only the standard range 1–3,999 is supported (no vinculum notation for larger numbers).
Privacy
Your text is processed entirely in this browser tab. Nothing is uploaded, logged or saved by this tool.
Local processing protects your data from being uploaded, but it cannot protect against a compromised device or malicious browser extensions.