Roman Numeral Converter
Convert whole numbers to Roman numerals and Roman numerals back to numbers, with validation, entirely in your browser.
Roman Numeral Output
MCMXCIV
Frequently Asked Questions
Is my data sent to a server when using the Roman Numeral Converter?
No. The Roman Numeral Converter is a fully client-side utility. All data processing, calculations, and conversions are handled locally in your browser. No input text, payloads, or keys are uploaded to any external server.
Why is the valid range limited to 1-3999?
Standard Roman numeral notation has no symbol for zero or negative numbers, and no single-letter symbol beyond M (1000), so 3999 (MMMCMXCIX) is the largest value representable without extending the system with special bar (vinculum) notation for multiplication by 1000.
What is subtractive notation in Roman numerals?
Subtractive notation places a smaller-value symbol before a larger one to indicate subtraction, such as IV for 4 (5 - 1) or IX for 9 (10 - 1), instead of writing four or nine repeated symbols in a row.
How does the converter validate Roman numeral input?
After parsing a Roman numeral to a number, the tool re-converts that number back to standard Roman notation and compares it against your uppercased input. If they don't match, it warns that the input doesn't look like standard Roman numeral notation, catching malformed or non-standard sequences.
Does the converter accept lowercase Roman numerals?
Yes. Input is automatically uppercased before parsing, so both `xiv` and `XIV` are accepted and treated identically.
Does the Roman Numeral Converter store history or cache my inputs?
No. The application runs entirely in browser memory. Once you refresh the tab, navigate away, or close the window, all inputted details, logs, and outputs are completely cleared.
Is the Roman Numeral Converter compatible with mobile devices?
Yes. The interface is optimized to be fully responsive. You can perform calculations, conversions, and formats on all modern mobile, tablet, and desktop web browsers.
Does the Roman Numeral Converter work offline?
Yes. Once loaded, all code and assets required to run the Roman Numeral Converter reside in your browser cache, enabling offline use without an active network connection.