Roman Numeral Converter
Convert between ordinary numbers and Roman numerals, both ways.
Quick answer: enter your details below and click Convert — your result appears instantly, right here in your browser. Nothing you enter is uploaded or stored.
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How to use
- Choose a conversion direction.
- Enter a number or a Roman numeral.
- Click Convert for the converted value.
About this tool
Choose a direction and enter a value. To Roman numerals, the tool builds the numeral with standard subtractive notation, so 4 is IV and 9 is IX, not IIII or VIIII. From Roman numerals, it reads the numeral back, handling subtractive pairs correctly.
Frequently asked questions
What is the largest number this tool handles?
3999, written MMMCMXCIX. Roman numerals have no standard zero or values beyond that in this converter.
Does it accept lowercase numerals?
Yes. Lowercase Roman numerals are converted to uppercase before reading.