Roman Numeral Converter
Valid from 1 to 3999. The reverse conversion also checks whether the Roman notation is correct.
Convert Roman numerals
The converter works both ways: Arabic numbers (e.g. 2026) to Roman (MMXXVI) and vice versa. It also detects invalid notations like “IIII” instead of “IV”.
- Range: The classic Roman system covers 1 to 3999.
- Subtraction rule: IV = 4, IX = 9, XL = 40 etc. – a smaller value before a larger one is subtracted.
- Validation: Only correctly written Roman numerals are accepted.