What range is supported?

Standard Roman numerals cover 1 to 3999. There is no symbol for zero, and numbers above 3999 need overlines that aren't part of plain text.

Does it validate Roman numerals?

Yes. Only canonical forms are accepted — 'IIII' and 'IL' are rejected, while 'IV' and 'XC' are valid. Lowercase input is accepted and treated as uppercase.

How does the conversion work?

Encoding greedily subtracts the largest values (M, CM, D, …); decoding adds each symbol, subtracting when a smaller symbol precedes a larger one (e.g. IV = 4).

Can I convert years and dates?

Yes. Any year from 1 to 3999 works, so 2024 becomes MMXXIV and 1994 becomes MCMXCIV. Paste the numeral from a clock face or film credit to read the year back as a normal number.

Roman Numeral Converter

Convert numbers to Roman numerals and back. Enter a number from 1 to 3999, or paste a Roman numeral to decode it.

Number

Result

MMXXIV

How to use it

Pick a direction, then type or paste into the box on the left. The conversion appears on the right and updates on every keystroke, so there is no button to press, and you copy the result when it looks right. Everything runs in your browser, so nothing is uploaded. In the Number to Roman direction, enter a whole number from 1 to 3999. The tool builds the numeral greedily, taking the largest value that fits at each step, so thousands come first as M characters, then the hundreds, tens, and ones. Where a digit is four or nine it uses the subtractive pairs the Romans preferred — IV for four, IX for nine, XL for forty, XC for ninety, CD for four hundred, and CM for nine hundred — rather than repeating a symbol four times. In the Roman to Number direction, paste a numeral and it is read back to a value. Input is case-insensitive, so mmxxiv and MMXXIV give the same answer, and only canonical forms are accepted: IIII and IL are rejected because standard notation writes IV and XLIX instead. When the input is not a valid numeral, the tool shows a hint rather than guessing a number, so you always know the result is trustworthy. As a worked example, the year 2024 becomes MMXXIV — two thousands, twenty as XX, and four as the subtractive IV. Going the other way, MCMXCIV reads back as 1994: M is 1000, CM is 900, XC is 90, and IV is 4. Because a smaller symbol placed before a larger one is subtracted, the order of the characters carries the arithmetic. Roman numerals still appear on clock faces, book chapters, film sequels, building cornerstones, and the year in film credits, so converting them is handy for reading dates, numbering outlines, or checking your own notation. The supported range of 1 to 3999 covers every year you are likely to meet, and since the whole conversion happens on your device it stays private.

Frequently asked questions

What range is supported?: Standard Roman numerals cover 1 to 3999. There is no symbol for zero, and numbers above 3999 need overlines that aren't part of plain text.
Does it validate Roman numerals?: Yes. Only canonical forms are accepted — 'IIII' and 'IL' are rejected, while 'IV' and 'XC' are valid. Lowercase input is accepted and treated as uppercase.
How does the conversion work?: Encoding greedily subtracts the largest values (M, CM, D, …); decoding adds each symbol, subtracting when a smaller symbol precedes a larger one (e.g. IV = 4).
Can I convert years and dates?: Yes. Any year from 1 to 3999 works, so 2024 becomes MMXXIV and 1994 becomes MCMXCIV. Paste the numeral from a clock face or film credit to read the year back as a normal number.