Roman Numeral Converter
Convert numbers to Roman numerals and back.
How to use the Roman Numeral Converter
Enter your values and pick a mode if the tool offers one.
Click calculate — results appear instantly, computed in your browser.
Copy the result or save the tool to your favorites.
Frequently asked questions
1 to 3999, the standard Roman numeral range.
Enter a Roman numeral like XIV and it returns the number.
Yes, they are read case-insensitively.
Romans had no zero, so 0 is not represented.
Entirely in your browser. Your data is never uploaded to a server.
About the Roman Numeral Converter
This tool converts ordinary numbers into Roman numerals and Roman numerals back into numbers. Enter a number such as 2024 to get MMXXIV, or enter a numeral like XIV to get 14. It works in both directions automatically, detecting whether you have typed digits or letters.
How the Roman system works
Roman numerals use seven letters with fixed values: I is 1, V is 5, X is 10, L is 50, C is 100, D is 500, and M is 1000. Numbers are built by combining these, generally from largest to smallest, adding the values together. So MMXXIV is 1000 plus 1000 plus 10 plus 10 plus 4. The system has no symbol for zero and no place value, which is part of why it was eventually replaced for calculation by the decimal system we use today.
The subtractive rule
The clever part of Roman numerals is subtraction. To avoid writing four identical symbols in a row, a smaller value placed before a larger one is subtracted rather than added. So 4 is IV (one before five) not IIII, and 9 is IX (one before ten). This applies in specific pairs: I before V or X, X before L or C, and C before D or M. The converter applies these rules automatically so the output follows standard form rather than a naive repetition.
The practical range
Standard Roman numerals run from 1 to 3999. There is no zero and no negative numbers, and representing values above 3999 requires bars over letters to multiply them by a thousand, a notation rarely used today. This tool works within the conventional 1 to 3999 range, which covers virtually every modern use.
Where Roman numerals are still used
Despite being ancient, Roman numerals persist in many places: clock faces, the copyright year on films and broadcasts, book chapter and volume numbers, the names of monarchs and popes, Super Bowl numbering, and building cornerstones. Knowing how to read and write them remains genuinely useful, and converting longer numerals by hand is error-prone, which is where this tool helps.
Tips and related tools
When decoding, the tool reads numerals case-insensitively, so xiv and XIV both work. If you enter an invalid numeral it will flag it rather than guess. For spelling numbers out in words instead, see the Number to Words Converter, and for converting between number bases the Number Base Converter. Everything runs instantly in your browser.