Roman Numerals Converter
Convert whole numbers between Arabic integers (1 to 3999) and classical Roman numerals in either direction.
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This online converter translates numbers between standard Arabic numerals and classical Roman numeral notation in both directions. When converting from Arabic integers to Roman numerals, the tool accepts whole numbers ranging from 1 through 3999. Values outside this standard range or non-integer entries cannot be processed. When converting from Roman numerals to Arabic numbers, you can enter standard Roman numeral letters such as I, V, X, L, C, D, and M. The converter automatically trims surrounding whitespace and handles lowercase letters by converting them to uppercase. It expects canonical Roman numeral formatting, meaning subtractive notation such as IV or IX is evaluated according to standard rules. After you run the tool, the output area displays the parsed integer, the formatted Roman numeral sequence, and the active conversion direction. Use this tool for historical dates, book chapter numbering, outlines, timepiece notations, or educational math exercises.
Instructions
- Select your preferred conversion direction from the Mode dropdown menu.
- Enter an integer between 1 and 3999 for Arabic to Roman conversion, or enter a canonical Roman numeral sequence for Roman to Arabic conversion.
- Click Run to perform the calculation.
- Review the converted numeric value and Roman numeral representation in the results panel.
Examples
- Convert Arabic integer 2024 to Roman numerals: select Arabic to Roman mode and enter 2024 to receive MMXXIV.
- Convert Roman numeral MCMXCIV to an Arabic number: select Roman to Arabic mode and enter MCMXCIV (or mcmxciv) to receive 1994.
FAQ
What is the maximum Arabic number this tool can convert to Roman numerals?
The Arabic to Roman conversion supports positive whole numbers from 1 through 3999 inclusive.
Does the converter accept lowercase Roman numeral letters?
Yes, Roman numeral inputs are normalized automatically so lowercase inputs such as mmxxiv are converted to uppercase.
What causes a Roman numeral conversion to fail?
Conversions fail if the input contains invalid characters, non-canonical Roman numeral sequences, non-integer numeric inputs, or numbers outside the 1 to 3999 range.