Roman Numeral Converter
Converts in both directions and detects which way you want automatically: type digits to get Roman numerals, type letters to get a number. The range is 1 to 3999, the limit of standard Roman notation without overline marks for thousands.
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Input
Result
Roman Numeral: MCMXCIX
About
What the Roman Numeral Converter does
The output uses correct subtractive notation, where a smaller numeral before a larger one means subtraction. This is why 4 is IV rather than IIII and 9 is IX rather than VIIII — and why 1999 is MCMXCIX, not MIM.
How it works
Using the Roman Numeral Converter
- 1Type either a number or a Roman numeral.
- 2The input is detected as digits or letters automatically.
- 3Numbers are converted greedily using the largest numeral values first.
- 4Roman numerals are read left to right, subtracting when a smaller value precedes a larger one.
- 5The converted value is displayed.
Use cases
What people use it for
- Reading a copyright date or building inscription
- Numbering chapters, appendices or acts
- Decoding a clock face or monument date
- Checking homework or a crossword answer
FAQ
Frequently asked questions
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