Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers.
Related Tools
0 comments
How it works
Converting a number to Roman numerals uses a greedy subtractive table — M, CM, D, CD, C, XC, L, XL, X, IX, V, IV, I — repeatedly subtracting the largest value that fits and appending its symbol, which produces standard forms like IV and IX rather than IIII. Converting the other way validates the input against the canonical Roman-numeral pattern before summing the symbol values, so malformed strings like VV or IIII are rejected. The supported range is 1 to 3999, the classic Roman system. All conversion runs locally.
2024 → MMXXIV
MCMLXXXIV → 1984
Common use cases
- Decoding a copyright year or clock face written in Roman numerals.
- Numbering chapters, appendices, or Super Bowl-style events.
- Checking a tattoo or engraving translates to the right number.
Frequently asked questions
What range of numbers is supported?
Standard Roman numerals cover 1 to 3999. There is no symbol for zero, and values above 3999 require overline notation that is rarely used, so they are outside this tool's range.
Why is IIII rejected?
Standard Roman numerals use subtractive notation: four is IV, not IIII. The converter validates against canonical forms, so non-standard spellings are flagged as invalid.
Is the conversion case-sensitive?
No. Lowercase Roman numerals are accepted and normalized, so iv and IV both convert to 4.