About the Roman Numeral Converter
Roman numerals still appear on clock faces, book chapters, film credits, monuments, Super Bowl numbering and tattoos of birth years. The system uses seven letters, and a smaller letter placed before a larger one is subtracted: IV is four, IX is nine, XL is forty and CM is nine hundred. This converter follows the standard subtractive rules in both directions and rejects malformed input such as IIII or VX.
The classical system stops at 3999, because there is no plain letter for five thousand. Larger numbers were written with a bar above a letter to multiply it by a thousand, a notation that does not survive well in plain text, so this tool covers 1 to 3999. To write a date, convert each part separately: 25 December 2026 is XXV, XII, MMXXVI.
How to use the Roman Numeral Converter
- Choose whether you are converting a number to Roman numerals or reading a numeral back.
- Type the number (1 to 3999) or the numeral (letters I, V, X, L, C, D and M).
- Read the converted value; the spaced-out version is handy for copying into a design or a tattoo.