Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers.
About the Roman Numeral Converter
Roman numerals are the number system used in ancient Rome, still seen today on clock faces, in movie copyright years, for book chapter numbers, and to denote monarchs and Super Bowls (like Super Bowl LVIII). This tool converts in both directions: type a regular number to get its Roman numeral form, or type Roman numerals to get the number back.
The standard system represents values using combinations of seven letters — I, V, X, L, C, D, and M — and supports whole numbers from 1 to 3,999, the practical range for the traditional subtractive notation (like IV for 4 or IX for 9).
Worked example
Example: converting 1994 returns MCMXCIV (1000 + 900 + 90 + 4), and converting the Roman numeral XLII back returns 42.
Frequently asked questions
- Why is there no Roman numeral for zero?
- The Roman numeral system predates the widespread use of zero as a number in Western mathematics — it was designed purely for counting and recording positive quantities, so it has no symbol for zero or negative numbers.
- What's the largest number Roman numerals can represent?
- Using standard notation, 3,999 (MMMCMXCIX) is the practical limit, since numerals aren't repeated more than three times in a row and there's no standard single symbol above M (1,000). Larger numbers historically used a bar over a numeral to multiply it by 1,000, which most modern converters (including this one) don't support.
- Why is 4 written as IV instead of IIII?
- This is 'subtractive notation': placing a smaller numeral before a larger one means subtract it (IV = 5 − 1 = 4) rather than add it. It's the standard modern convention, though IIII does appear historically and is still sometimes used on clock faces for visual symmetry.
- Does this handle lowercase Roman numerals?
- Yes — the numeral-to-number direction accepts lowercase letters (like 'xlii') and treats them the same as uppercase, since case doesn't change the value.