Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals to numbers.
How to Use the Roman Numeral Converter
This tool converts between standard (Arabic) numbers and Roman numerals:
- Choose a mode — select "Number → Roman" to convert a decimal number into a Roman numeral, or "Roman → Number" to convert a Roman numeral into a decimal number.
- Type your value — enter a whole number from 1 to 3999, or a valid Roman numeral such as XIV or MCMXCIV.
- Read the result — the conversion updates instantly as you type.
- Copy the result — click the Copy button to copy the converted value to your clipboard.
All conversions happen instantly in your browser. No data is sent to any server.
Frequently Asked Questions
What numbers can I convert to Roman numerals?
Standard Roman numerals represent numbers from 1 to 3999. Numbers outside this range do not have a conventional Roman numeral representation.
What do the Roman numeral letters mean?
I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1000. Combinations use subtractive notation: IV = 4, IX = 9, XL = 40, XC = 90, CD = 400 and CM = 900.
How does subtractive notation work?
When a smaller-value numeral appears before a larger one it is subtracted. For example, IV means 5 minus 1 = 4, and XC means 100 minus 10 = 90.
Are lowercase Roman numerals accepted?
Yes. The converter accepts both uppercase (XIV) and lowercase (xiv) input and will still produce the correct result.
Why is 3999 the maximum?
The largest number expressible with the seven standard Roman numeral symbols (I, V, X, L, C, D, M) without extension bars is MMMCMXCIX = 3999.
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