Roman numerals
Convert Arabic numbers to Roman numerals and back. Validates numeral syntax and rejects malformed or non-standard combinations.
Enter a number or Roman numeral.
// About this tool
Translate between Roman numerals and everyday numbers for documents, dates, or study. Invalid or non-canonical numerals are rejected rather than guessed.
// How to use it
- Enter an Arabic number or Roman numeral.
- Review the converted value.
- Copy the result for your document.
// Frequently asked questions
Which values are supported?
Positive integers that have a standard Roman numeral representation.
Why is my numeral rejected?
The input must use valid symbols in the canonical order; malformed strings are not converted.