Roman numeral converter
Convert whole numbers to Roman numerals or check and decode standard Roman numeral notation.
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How to use this tool
- Choose a direction and enter one whole number or one Roman numeral.
- Run the conversion. Invalid numeral order or repetition is reported with the standard-notation requirement.
Things to know
- Whole numbers 1-3999 using I, V, X, L, C, D and M. Zero, fractions, overbars and historical additive variants are not supported.
- Letter case is ignored when decoding. The input must match modern subtractive notation, such as IV and IX.
- Processing stays on your device. Results are not saved between visits.
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